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Merge pull request #9004 from Bob-the-Kuhn/PWM-for-any-pin-(LPC1768)

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[2.0.x] LPC1768 - PWM for any pin (replaces PR #8991)
2.0.x
Bob-the-Kuhn 7 years ago committed by GitHub
parent d190c702de 5574fad69c
commit 448b0a0014
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3 changed files with 305 additions and 314 deletions
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5
Marlin/src/HAL/HAL_LPC1768/HAL_timers.h
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@ -66,6 +66,11 @@ typedef uint32_t hal_timer_t;
#define HAL_STEP_TIMER_ISR extern "C" void TIMER0_IRQHandler(void) #define HAL_STEP_TIMER_ISR extern "C" void TIMER0_IRQHandler(void)
#define HAL_TEMP_TIMER_ISR extern "C" void TIMER1_IRQHandler(void) #define HAL_TEMP_TIMER_ISR extern "C" void TIMER1_IRQHandler(void)
// PWM timer
#define HAL_PWM_TIMER LPC_TIM3
#define HAL_PWM_TIMER_ISR extern "C" void TIMER3_IRQHandler(void)
#define HAL_PWM_TIMER_IRQn TIMER3_IRQn
// -------------------------------------------------------------------------- // --------------------------------------------------------------------------
// Types // Types
// -------------------------------------------------------------------------- // --------------------------------------------------------------------------

610
Marlin/src/HAL/HAL_LPC1768/LPC1768_PWM.cpp
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@ -32,7 +32,7 @@
* The PWM1 module is used to directly control the Servo 0, 1 & 3 pins and D9 & D10 pins. This keeps * The PWM1 module is used to directly control the Servo 0, 1 & 3 pins and D9 & D10 pins. This keeps
* the pulse width jitter to under a microsecond. * the pulse width jitter to under a microsecond.
* *
* For all other pins the PWM1 module is used to generate interrupts. The ISR * For all other pins a timer is used to generate interrupts. The ISR
* routine does the actual setting/clearing of pins. The upside is that any pin can * routine does the actual setting/clearing of pins. The upside is that any pin can
* have a PWM channel assigned to it. The downside is that there is more pulse width * have a PWM channel assigned to it. The downside is that there is more pulse width
* jitter. The jitter depends on what else is happening in the system and what ISRs * jitter. The jitter depends on what else is happening in the system and what ISRs
@ -41,25 +41,11 @@
/** /**
* The data structures are set up to minimize the computation done by the ISR which * The data structures are set up to minimize the computation done by the ISR which
* minimizes ISR execution time. Execution times are 2-4µs except when updating to * minimizes ISR execution time. Execution times are 5-14µs depending on how full the
* a new value when they are 19µs. * ISR table is. 14uS is for a 20 element ISR table.
* *
* Two tables are used. One table contains the data used by the ISR to update/control * Two tables are used. One table contains the data used by the ISR to update/control
* the PWM pins. The other is used as an aid when rebuilding the ISR table. * the PWM pins. The other is used as an aid when updating the ISR table.
*
* The LPC1768_PWM_attach_pin routine disables the ISR and then adds the new info to
* ISR table. It can update the table directly because none of its changes affect
* what the ISR does.
*
* LPC1768_PWM_detach_pin routine disables the ISR, disables the pin immediately if
* it's a directly controlled pin and updates the helper table. It then flags the
* ISR that the ISR table needs to be rebuilt.
*
* LPC1768_PWM_write routine disables the ISR and updates the helper table. It then
* flags the ISR that the ISR table needs to be rebuilt.
*
* The ISR's priority is set to less than the stepper ISR otherwise it could cause jitter
* in the step pulses.
* *
* See the end of this file for details on the hardware/firmware interaction * See the end of this file for details on the hardware/firmware interaction
*/ */
@ -86,46 +72,36 @@
#ifdef TARGET_LPC1768 #ifdef TARGET_LPC1768
#include "../../inc/MarlinConfig.h" #include "../../inc/MarlinConfig.h"
#include <lpc17xx_pinsel.h> #include <lpc17xx_pinsel.h>
#include "LPC1768_PWM.h" #include "LPC1768_PWM.h"
#include "arduino.h" #include "arduino.h"
#define NUM_PWMS 6 #define NUM_ISR_PWMS 20
#define LPC_PORT_OFFSET (0x0020)
#define LPC_PIN(pin) (1UL << pin)
#define LPC_GPIO(port) ((volatile LPC_GPIO_TypeDef *)(LPC_GPIO0_BASE + LPC_PORT_OFFSET * port))
typedef struct { // holds all data needed to control/init one of the PWM channels typedef struct { // holds all data needed to control/init one of the PWM channels
uint8_t sequence; // 0: available slot, 1 - 6: PWM channel assigned to that slot bool active_flag; // THIS TABLE ENTRY IS ACTIVELY TOGGLING A PIN
pin_t pin; pin_t pin;
uint16_t PWM_mask; // MASK TO CHECK/WRITE THE IR REGISTER
volatile uint32_t* set_register; volatile uint32_t* set_register;
volatile uint32_t* clr_register; volatile uint32_t* clr_register;
uint32_t write_mask; // USED BY SET/CLEAR COMMANDS uint32_t write_mask; // USED BY SET/CLEAR COMMANDS
uint32_t microseconds; // value written to MR register uint32_t microseconds; // value written to MR register
uint32_t min; // lower value limit checked by WRITE routine before writing to the MR register uint32_t min; // lower value limit checked by WRITE routine before writing to the MR register
uint32_t max; // upper value limit checked by WRITE routine before writing to the MR register uint32_t max; // upper value limit checked by WRITE routine before writing to the MR register
bool PWM_flag; // 0 - USED BY hardware PWM, 1 - USED BY ANALOGWRITE
uint8_t servo_index; // 0 - MAX_SERVO -1 : servo index, 0xFF : PWM channel uint8_t servo_index; // 0 - MAX_SERVO -1 : servo index, 0xFF : PWM channel
bool active_flag; // THIS TABLE ENTRY IS ACTIVELY TOGGLING A PIN
uint32_t PCR_bit; // PCR register bit to enable PWM1 control of this pin
volatile uint32_t* PINSEL_reg; // PINSEL register
uint32_t PINSEL_bits; // PINSEL register bits to set pin mode to PWM1 control
} PWM_map; } PWM_map;
PWM_map PWM1_map_A[NUM_ISR_PWMS]; // compiler will initialize to all zeros
PWM_map PWM1_map_B[NUM_ISR_PWMS]; // compiler will initialize to all zeros
#define MICRO_MAX 0xFFFFFFFF PWM_map *active_table = PWM1_map_A;
PWM_map *work_table = PWM1_map_B;
#define PWM_MAP_INIT_ROW { 0, 0x7FFF, 0, 0, 0, 0, MICRO_MAX, 0, 0, 0, 0, 0, 0, 0, 0 } PWM_map *temp_table;
#define PWM_MAP_INIT { PWM_MAP_INIT_ROW, PWM_MAP_INIT_ROW, PWM_MAP_INIT_ROW, \
PWM_MAP_INIT_ROW, PWM_MAP_INIT_ROW, PWM_MAP_INIT_ROW, \
};
PWM_map ISR_table[NUM_PWMS] = PWM_MAP_INIT;
#define IR_BIT(p) ((p) >= 0 && (p) <= 3 ? (p) : p + 4 )
#define PIN_IS_INVERTED(p) 0 // placeholder in case inverting PWM output is offered
#define P1_18_PWM_channel 1 // servo 3 #define P1_18_PWM_channel 1 // servo 3
#define P1_20_PWM_channel 2 // servo 0 #define P1_20_PWM_channel 2 // servo 0
@ -134,35 +110,13 @@ PWM_map ISR_table[NUM_PWMS] = PWM_MAP_INIT;
#define P2_04_PWM_channel 5 // D9 #define P2_04_PWM_channel 5 // D9
#define P2_05_PWM_channel 6 // D10 #define P2_05_PWM_channel 6 // D10
// used to keep track of which Match Registers have been used and if they will be used by the typedef struct {
// PWM1 module to directly control the pin or will be used to generate an interrupt uint32_t min;
typedef struct { // status of PWM1 channel uint32_t max;
uint8_t map_used; // 0 - this MR register not used/assigned bool assigned;
uint8_t map_PWM_INT; // 0 - available for interrupts, 1 - in use by PWM } table_direct;
pin_t map_PWM_PIN; // pin for this PwM1 controlled pin / port
volatile uint32_t* MR_register; // address of the MR register for this PWM1 channel table_direct direct_table[6]; // compiler will initialize to all zeros
uint32_t PCR_bit; // PCR register bit to enable PWM1 control of this pin
// 0 - don't switch to PWM1 direct control
volatile uint32_t* PINSEL_reg; // PINSEL register
uint32_t PINSEL_bits; // PINSEL register bits to set pin mode to PWM1 control
} MR_map;
MR_map map_MR[NUM_PWMS];
void LPC1768_PWM_update_map_MR(void) {
map_MR[0] = { 0, (uint8_t) (LPC_PWM1->PCR & _BV(8 + P1_18_PWM_channel) ? 1 : 0), P1_18, &LPC_PWM1->MR1, 0, 0, 0 };
map_MR[1] = { 0, (uint8_t) (LPC_PWM1->PCR & _BV(8 + P1_20_PWM_channel) ? 1 : 0), P1_20, &LPC_PWM1->MR2, 0, 0, 0 };
map_MR[2] = { 0, (uint8_t) (LPC_PWM1->PCR & _BV(8 + P1_21_PWM_channel) ? 1 : 0), P1_21, &LPC_PWM1->MR3, 0, 0, 0 };
map_MR[3] = {
#if MB(MKS_SBASE)
0, (uint8_t) (LPC_PWM1->PCR & _BV(8 + P1_23_PWM_channel) ? 1 : 0), P1_23, &LPC_PWM1->MR4, 0, 0, 0
#else
0, 0, P_NC, &LPC_PWM1->MR4, 0, 0, 0
#endif
};
map_MR[4] = { 0, (uint8_t) (LPC_PWM1->PCR & _BV(8 + P2_04_PWM_channel) ? 1 : 0), P2_04, &LPC_PWM1->MR5, 0, 0, 0 };
map_MR[5] = { 0, (uint8_t) (LPC_PWM1->PCR & _BV(8 + P2_05_PWM_channel) ? 1 : 0), P2_05, &LPC_PWM1->MR6, 0, 0, 0 };
}
/** /**
* Prescale register and MR0 register values * Prescale register and MR0 register values
@ -181,8 +135,8 @@ void LPC1768_PWM_update_map_MR(void) {
* 0.25 399 4,999 199 4,999 99 4,999 49 4,999 0.720 * 0.25 399 4,999 199 4,999 99 4,999 49 4,999 0.720
* 0.125 799 2,499 399 2,499 199 2,499 99 2,499 1.440 * 0.125 799 2,499 399 2,499 199 2,499 99 2,499 1.440
* *
* The desired prescale frequency comes from an input in the range of 544 - 2400 microseconds and the * The desired prescale frequency column comes from an input in the range of 544 - 2400 microseconds
* desire to just shift the input left or right as needed. * and the desire to just shift the input left or right as needed.
* *
* A resolution of 0.2 degrees seems reasonable so a prescale frequency output of 1MHz is being used. * A resolution of 0.2 degrees seems reasonable so a prescale frequency output of 1MHz is being used.
* It also means we don't need to scale the input. * It also means we don't need to scale the input.
@ -197,9 +151,10 @@ void LPC1768_PWM_update_map_MR(void) {
* *
*/ */
bool ISR_table_update = false; // flag to tell the ISR that the tables need to be updated & swapped
void LPC1768_PWM_init(void) { void LPC1768_PWM_init(void) {
///// directly controlled PWM pins (interrupts not used for these)
#define SBIT_CNTEN 0 // PWM1 counter & pre-scaler enable/disable #define SBIT_CNTEN 0 // PWM1 counter & pre-scaler enable/disable
#define SBIT_CNTRST 1 // reset counters to known state #define SBIT_CNTRST 1 // reset counters to known state
#define SBIT_PWMEN 3 // 1 - PWM, 0 - timer #define SBIT_PWMEN 3 // 1 - PWM, 0 - timer
@ -221,43 +176,116 @@ void LPC1768_PWM_init(void) {
LPC_PWM1->LER = 0x07F; // Set the latch Enable Bits to load the new Match Values for MR0 - MR6 LPC_PWM1->LER = 0x07F; // Set the latch Enable Bits to load the new Match Values for MR0 - MR6
LPC_PWM1->PCR = 0; // Single edge mode for all channels, PWM1 control of outputs off LPC_PWM1->PCR = 0; // Single edge mode for all channels, PWM1 control of outputs off
NVIC_EnableIRQ(PWM1_IRQn); // Enable interrupt handler //// interrupt controlled PWM setup
NVIC_SetPriority(PWM1_IRQn, NVIC_EncodePriority(0, 10, 0)); // Normal priority for PWM module
//NVIC_SetPriority(PWM1_IRQn, NVIC_EncodePriority(0, 0, 0)); // Minimizes jitter due to higher priority ISRs LPC_SC->PCONP |= 1 << 23; // power on timer3
HAL_PWM_TIMER->PR = LPC_PWM1_PR;
HAL_PWM_TIMER->MCR = 0x0B; // Interrupt on MR0 & MR1, reset on MR0
HAL_PWM_TIMER->MR0 = LPC_PWM1_MR0;
HAL_PWM_TIMER->MR1 = 0;
HAL_PWM_TIMER->TCR = _BV(0); // enable
NVIC_EnableIRQ(HAL_PWM_TIMER_IRQn);
NVIC_SetPriority(HAL_PWM_TIMER_IRQn, NVIC_EncodePriority(0, 4, 0));
} }
bool LPC1768_PWM_attach_pin(pin_t pin, uint32_t min /* = 1 */, uint32_t max /* = (LPC_PWM1_MR0 - MR0_MARGIN) */, uint8_t servo_index /* = 0xff */) { bool ISR_table_update = false; // flag to tell the ISR that the tables need to be updated & swapped
uint8_t ISR_index = 0; // index used by ISR to skip already actioned entries
#define COPY_ACTIVE_TABLE for (uint8_t i = 0; i < NUM_ISR_PWMS ; i++) work_table[i] = active_table[i]
uint32_t first_MR1_value = LPC_PWM1_MR0 + 1;
void LPC1768_PWM_sort(void) {
for (uint8_t i = NUM_ISR_PWMS; --i;) { // (bubble) sort table by microseconds
bool didSwap = false;
PWM_map temp;
for (uint16_t j = 0; j < i; ++j) {
if (work_table[j].microseconds > work_table[j + 1].microseconds) {
temp = work_table[j + 1];
work_table[j + 1] = work_table[j];
work_table[j] = temp;
didSwap = true;
}
}
if (!didSwap) break;
}
}
bool LPC1768_PWM_attach_pin(pin_t pin, uint32_t min /* = 1 */, uint32_t max /* = (LPC_PWM1_MR0 - 1) */, uint8_t servo_index /* = 0xff */) {
pin = GET_PIN_MAP_PIN(GET_PIN_MAP_INDEX(pin & 0xFF)); // Sometimes the upper byte is garbled pin = GET_PIN_MAP_PIN(GET_PIN_MAP_INDEX(pin & 0xFF)); // Sometimes the upper byte is garbled
NVIC_DisableIRQ(PWM1_IRQn); // make it safe to update the active table //// direct control PWM code
switch(pin) {
case P1_23: // MKS Sbase Servo 0, PWM1 channel 4 (J3-8 PWM1.4)
direct_table[P1_23_PWM_channel - 1].min = min;
direct_table[P1_23_PWM_channel - 1].max = MIN(max, LPC_PWM1_MR0 - MR0_MARGIN);
direct_table[P1_23_PWM_channel - 1].assigned = true;
return true;
case P1_20: // Servo 0, PWM1 channel 2 (Pin 11 P1.20 PWM1.2)
direct_table[P1_20_PWM_channel - 1].min = min;
direct_table[P1_20_PWM_channel - 1].max = MIN(max, LPC_PWM1_MR0 - MR0_MARGIN);
direct_table[P1_20_PWM_channel - 1].assigned = true;
return true;
case P1_21: // Servo 1, PWM1 channel 3 (Pin 6 P1.21 PWM1.3)
direct_table[P1_21_PWM_channel - 1].min = min;
direct_table[P1_21_PWM_channel - 1].max = MIN(max, LPC_PWM1_MR0 - MR0_MARGIN);
direct_table[P1_21_PWM_channel - 1].assigned = true;
return true;
case P1_18: // Servo 3, PWM1 channel 1 (Pin 4 P1.18 PWM1.1)
direct_table[P1_18_PWM_channel - 1].min = min;
direct_table[P1_18_PWM_channel - 1].max = MIN(max, LPC_PWM1_MR0 - MR0_MARGIN);
direct_table[P1_18_PWM_channel - 1].assigned = true;
return true;
case P2_04: // D9 FET, PWM1 channel 5 (Pin 9 P2_04 PWM1.5)
direct_table[P2_04_PWM_channel - 1].min = min;
direct_table[P2_04_PWM_channel - 1].max = MIN(max, LPC_PWM1_MR0 - MR0_MARGIN);
direct_table[P2_04_PWM_channel - 1].assigned = true;
return true;
case P2_05: // D10 FET, PWM1 channel 6 (Pin 10 P2_05 PWM1.6)
direct_table[P2_05_PWM_channel - 1].min = min;
direct_table[P2_05_PWM_channel - 1].max = MIN(max, LPC_PWM1_MR0 - MR0_MARGIN);
direct_table[P2_05_PWM_channel - 1].assigned = true;
return true;
}
//// interrupt controlled PWM code
NVIC_DisableIRQ(HAL_PWM_TIMER_IRQn); // make it safe to update the active table
// OK to update the active table because the // OK to update the active table because the
// ISR doesn't use any of the changed items // ISR doesn't use any of the changed items
if (ISR_table_update) //use work table if that's the newest
temp_table = work_table;
else
temp_table = active_table;
uint8_t slot = 0; uint8_t slot = 0;
for (uint8_t i = 0; i < NUM_PWMS ; i++) // see if already in table for (uint8_t i = 0; i < NUM_ISR_PWMS; i++) // see if already in table
if (ISR_table[i].pin == pin) { if (temp_table[i].pin == pin) {
NVIC_EnableIRQ(PWM1_IRQn); // re-enable PWM interrupts NVIC_EnableIRQ(HAL_PWM_TIMER_IRQn); // re-enable PWM interrupts
return 1; return 1;
} }
for (uint8_t i = 1; (i < NUM_PWMS + 1) && !slot; i++) // find empty slot for (uint8_t i = 1; (i < NUM_ISR_PWMS + 1) && !slot; i++) // find empty slot
if ( !(ISR_table[i - 1].set_register)) { slot = i; break; } // any item that can't be zero when active or just attached is OK if ( !(temp_table[i - 1].set_register)) { slot = i; break; } // any item that can't be zero when active or just attached is OK
if (!slot) return 0;
if (!slot) {
NVIC_EnableIRQ(HAL_PWM_TIMER_IRQn); // re-enable PWM interrupts
return 0;
}
slot--; // turn it into array index slot--; // turn it into array index
ISR_table[slot].pin = pin; // init slot temp_table[slot].pin = pin; // init slot
ISR_table[slot].PWM_mask = 0; // real value set by PWM_write temp_table[slot].set_register = &LPC_GPIO(LPC1768_PIN_PORT(pin))->FIOSET;
ISR_table[slot].set_register = PIN_IS_INVERTED(pin) ? &LPC_GPIO(LPC1768_PIN_PORT(pin))->FIOCLR : &LPC_GPIO(LPC1768_PIN_PORT(pin))->FIOSET; temp_table[slot].clr_register = &LPC_GPIO(LPC1768_PIN_PORT(pin))->FIOCLR;
ISR_table[slot].clr_register = PIN_IS_INVERTED(pin) ? &LPC_GPIO(LPC1768_PIN_PORT(pin))->FIOSET : &LPC_GPIO(LPC1768_PIN_PORT(pin))->FIOCLR; temp_table[slot].write_mask = LPC_PIN(LPC1768_PIN_PIN(pin));
ISR_table[slot].write_mask = LPC_PIN(LPC1768_PIN_PIN(pin)); temp_table[slot].min = min;
ISR_table[slot].microseconds = MICRO_MAX; temp_table[slot].max = max; // different max for ISR PWMs than for direct PWMs
ISR_table[slot].min = min; temp_table[slot].servo_index = servo_index;
ISR_table[slot].max = MIN(max, LPC_PWM1_MR0 - MR0_MARGIN); temp_table[slot].active_flag = false;
ISR_table[slot].servo_index = servo_index;
ISR_table[slot].active_flag = false;
NVIC_EnableIRQ(PWM1_IRQn); // re-enable PWM interrupts NVIC_EnableIRQ(HAL_PWM_TIMER_IRQn); // re-enable PWM interrupts
return 1; return 1;
} }
@ -267,201 +295,154 @@ bool LPC1768_PWM_detach_pin(pin_t pin) {
pin = GET_PIN_MAP_PIN(GET_PIN_MAP_INDEX(pin & 0xFF)); pin = GET_PIN_MAP_PIN(GET_PIN_MAP_INDEX(pin & 0xFF));
NVIC_DisableIRQ(PWM1_IRQn); //// direct control PWM code
uint8_t slot = 0xFF;
for (uint8_t i = 0; i < NUM_PWMS; i++) // find slot
if (ISR_table[i].pin == pin) { slot = i; break; }
if (slot == 0xFF) { // return error if pin not found
NVIC_EnableIRQ(PWM1_IRQn);
return false;
}
LPC1768_PWM_update_map_MR();
// OK to make these changes before the MR0 interrupt
switch(pin) { switch(pin) {
case P1_23: // MKS Sbase Servo 0, PWM1 channel 4 (J3-8 PWM1.4) case P1_23: // MKS Sbase Servo 0, PWM1 channel 4 (J3-8 PWM1.4)
if (!direct_table[P1_23_PWM_channel - 1].assigned) return false;
CBI(LPC_PWM1->PCR, 8 + P1_23_PWM_channel); // disable PWM1 module control of this pin CBI(LPC_PWM1->PCR, 8 + P1_23_PWM_channel); // disable PWM1 module control of this pin
map_MR[P1_23_PWM_channel - 1].PCR_bit = 0;
LPC_PINCON->PINSEL3 &= ~(0x3 << 14); // return pin to general purpose I/O LPC_PINCON->PINSEL3 &= ~(0x3 << 14); // return pin to general purpose I/O
map_MR[P1_23_PWM_channel - 1].PINSEL_bits = 0; direct_table[P1_23_PWM_channel - 1].assigned = false;
map_MR[P1_23_PWM_channel - 1].map_PWM_INT = 0; // 0 - available for interrupts, 1 - in use by PWM return true;
break;
case P1_20: // Servo 0, PWM1 channel 2 (Pin 11 P1.20 PWM1.2) case P1_20: // Servo 0, PWM1 channel 2 (Pin 11 P1.20 PWM1.2)
if (!direct_table[P1_20_PWM_channel - 1].assigned) return false;
CBI(LPC_PWM1->PCR, 8 + P1_20_PWM_channel); // disable PWM1 module control of this pin CBI(LPC_PWM1->PCR, 8 + P1_20_PWM_channel); // disable PWM1 module control of this pin
map_MR[P1_20_PWM_channel - 1].PCR_bit = 0;
LPC_PINCON->PINSEL3 &= ~(0x3 << 8); // return pin to general purpose I/O LPC_PINCON->PINSEL3 &= ~(0x3 << 8); // return pin to general purpose I/O
map_MR[P1_20_PWM_channel - 1].PINSEL_bits = 0; direct_table[P1_20_PWM_channel - 1].assigned = false;
map_MR[P1_20_PWM_channel - 1].map_PWM_INT = 0; // 0 - available for interrupts, 1 - in use by PWM return true;
break;
case P1_21: // Servo 1, PWM1 channel 3 (Pin 6 P1.21 PWM1.3) case P1_21: // Servo 1, PWM1 channel 3 (Pin 6 P1.21 PWM1.3)
if (!direct_table[P1_21_PWM_channel - 1].assigned) return false;
CBI(LPC_PWM1->PCR, 8 + P1_21_PWM_channel); // disable PWM1 module control of this pin CBI(LPC_PWM1->PCR, 8 + P1_21_PWM_channel); // disable PWM1 module control of this pin
map_MR[P1_21_PWM_channel - 1].PCR_bit = 0;
LPC_PINCON->PINSEL3 &= ~(0x3 << 10); // return pin to general purpose I/O LPC_PINCON->PINSEL3 &= ~(0x3 << 10); // return pin to general purpose I/O
map_MR[P1_21_PWM_channel - 1].PINSEL_bits = 0; direct_table[P1_21_PWM_channel - 1].assigned = false;
map_MR[P1_21_PWM_channel - 1].map_PWM_INT = 0; // 0 - available for interrupts, 1 - in use by PWM return true;
break;
case P1_18: // Servo 3, PWM1 channel 1 (Pin 4 P1.18 PWM1.1) case P1_18: // Servo 3, PWM1 channel 1 (Pin 4 P1.18 PWM1.1)
if (!direct_table[P1_18_PWM_channel - 1].assigned) return false;
CBI(LPC_PWM1->PCR, 8 + P1_18_PWM_channel); // disable PWM1 module control of this pin CBI(LPC_PWM1->PCR, 8 + P1_18_PWM_channel); // disable PWM1 module control of this pin
map_MR[P1_18_PWM_channel - 1].PCR_bit = 0;
LPC_PINCON->PINSEL3 &= ~(0x3 << 4); // return pin to general purpose I/O LPC_PINCON->PINSEL3 &= ~(0x3 << 4); // return pin to general purpose I/O
map_MR[P1_18_PWM_channel - 1].PINSEL_bits = 0; direct_table[P1_18_PWM_channel - 1].assigned = false;
map_MR[P1_18_PWM_channel - 1].map_PWM_INT = 0; // 0 - available for interrupts, 1 - in use by PWM return true;
break;
case P2_04: // D9 FET, PWM1 channel 5 (Pin 9 P2_04 PWM1.5) case P2_04: // D9 FET, PWM1 channel 5 (Pin 9 P2_04 PWM1.5)
if (!direct_table[P2_04_PWM_channel - 1].assigned) return false;
CBI(LPC_PWM1->PCR, 8 + P2_04_PWM_channel); // disable PWM1 module control of this pin CBI(LPC_PWM1->PCR, 8 + P2_04_PWM_channel); // disable PWM1 module control of this pin
map_MR[P2_04_PWM_channel - 1].PCR_bit = 0;
LPC_PINCON->PINSEL4 &= ~(0x3 << 10); // return pin to general purpose I/O LPC_PINCON->PINSEL4 &= ~(0x3 << 10); // return pin to general purpose I/O
map_MR[P2_04_PWM_channel - 1].PINSEL_bits = 0; direct_table[P2_04_PWM_channel - 1].assigned = false;
map_MR[P2_04_PWM_channel - 1].map_PWM_INT = 0; // 0 - available for interrupts, 1 - in use by PWM return true;
break;
case P2_05: // D10 FET, PWM1 channel 6 (Pin 10 P2_05 PWM1.6) case P2_05: // D10 FET, PWM1 channel 6 (Pin 10 P2_05 PWM1.6)
if (!direct_table[P2_05_PWM_channel - 1].assigned) return false;
CBI(LPC_PWM1->PCR, 8 + P2_05_PWM_channel); // disable PWM1 module control of this pin CBI(LPC_PWM1->PCR, 8 + P2_05_PWM_channel); // disable PWM1 module control of this pin
map_MR[P2_05_PWM_channel - 1].PCR_bit = 0;
LPC_PINCON->PINSEL4 &= ~(0x3 << 4); // return pin to general purpose I/O LPC_PINCON->PINSEL4 &= ~(0x3 << 4); // return pin to general purpose I/O
map_MR[P2_05_PWM_channel - 1].PINSEL_bits = 0; direct_table[P2_05_PWM_channel - 1].assigned = false;
map_MR[P2_05_PWM_channel - 1].map_PWM_INT = 0; // 0 - available for interrupts, 1 - in use by PWM return true;
break; }
default:
//// interrupt controlled PWM code
NVIC_DisableIRQ(HAL_PWM_TIMER_IRQn);
if (ISR_table_update) {
ISR_table_update = false; // don't update yet - have another update to do
NVIC_EnableIRQ(HAL_PWM_TIMER_IRQn); // re-enable PWM interrupts
}
else {
NVIC_EnableIRQ(HAL_PWM_TIMER_IRQn); // re-enable PWM interrupts
COPY_ACTIVE_TABLE; // copy active table into work table
}
uint8_t slot = 0xFF;
for (uint8_t i = 0; i < NUM_ISR_PWMS; i++) { // find slot
if (work_table[i].pin == pin) {
slot = i;
break; break;
}
} }
if (slot == 0xFF) // return error if pin not found
return false;
ISR_table[slot] = PWM_MAP_INIT_ROW; work_table[slot] = {0, 0, 0, 0, 0, 0, 0, 0, 0};
LPC1768_PWM_sort(); // sort table by microseconds
ISR_table_update = true; ISR_table_update = true;
NVIC_EnableIRQ(PWM1_IRQn); // re-enable PWM interrupts return true;
return 1;
} }
// value is 0-20,000 microseconds (0% to 100% duty cycle)
// servo routine provides values in the 544 - 2400 range
bool LPC1768_PWM_write(pin_t pin, uint32_t value) { bool LPC1768_PWM_write(pin_t pin, uint32_t value) {
pin = GET_PIN_MAP_PIN(GET_PIN_MAP_INDEX(pin & 0xFF)); pin = GET_PIN_MAP_PIN(GET_PIN_MAP_INDEX(pin & 0xFF));
NVIC_DisableIRQ(PWM1_IRQn); //// direct control PWM code
uint8_t slot = 0xFF;
for (uint8_t i = 0; i < NUM_PWMS; i++) // find slot
if (ISR_table[i].pin == pin) { slot = i; break; }
if (slot == 0xFF) { // return error if pin not found
NVIC_EnableIRQ(PWM1_IRQn);
return false;
}
LPC1768_PWM_update_map_MR();
switch(pin) { switch(pin) {
case P1_23: // MKS Sbase Servo 0, PWM1 channel 4 (J3-8 PWM1.4) case P1_23: // MKS Sbase Servo 0, PWM1 channel 4 (J3-8 PWM1.4)
map_MR[P1_23_PWM_channel - 1].PCR_bit = _BV(8 + P1_23_PWM_channel); // enable PWM1 module control of this pin if (!direct_table[P1_23_PWM_channel - 1].assigned) return false;
map_MR[P1_23_PWM_channel - 1].PINSEL_reg = &LPC_PINCON->PINSEL3; LPC_PWM1->PCR |= _BV(8 + P1_23_PWM_channel); // enable PWM1 module control of this pin
map_MR[P1_23_PWM_channel - 1].PINSEL_bits = 0x2 << 14; // ISR must do this AFTER setting PCR LPC_PINCON->PINSEL3 = 0x2 << 14; // must set pin function AFTER setting PCR
break; // load the new time value
LPC_PWM1->MR4 = MAX(MIN(value, direct_table[P1_23_PWM_channel - 1].max), direct_table[P1_23_PWM_channel - 1].min);
LPC_PWM1->LER = 0x1 << P1_23_PWM_channel; // Set the latch Enable Bit to load the new Match Value on the next MR0
return true;
case P1_20: // Servo 0, PWM1 channel 2 (Pin 11 P1.20 PWM1.2) case P1_20: // Servo 0, PWM1 channel 2 (Pin 11 P1.20 PWM1.2)
map_MR[P1_20_PWM_channel - 1].PCR_bit = _BV(8 + P1_20_PWM_channel); // enable PWM1 module control of this pin if (!direct_table[P1_20_PWM_channel - 1].assigned) return false;
map_MR[P1_20_PWM_channel - 1].PINSEL_reg = &LPC_PINCON->PINSEL3; LPC_PWM1->PCR |= _BV(8 + P1_20_PWM_channel); // enable PWM1 module control of this pin
map_MR[P1_20_PWM_channel - 1].PINSEL_bits = 0x2 << 8; // ISR must do this AFTER setting PCR LPC_PINCON->PINSEL3 |= 0x2 << 8; // must set pin function AFTER setting PCR
break; // load the new time value
LPC_PWM1->MR2 = MAX(MIN(value, direct_table[P1_20_PWM_channel - 1].max), direct_table[P1_20_PWM_channel - 1].min);
LPC_PWM1->LER = 0x1 << P1_20_PWM_channel; // Set the latch Enable Bit to load the new Match Value on the next MR0
return true;
case P1_21: // Servo 1, PWM1 channel 3 (Pin 6 P1.21 PWM1.3) case P1_21: // Servo 1, PWM1 channel 3 (Pin 6 P1.21 PWM1.3)
map_MR[P1_21_PWM_channel - 1].PCR_bit = _BV(8 + P1_21_PWM_channel); // enable PWM1 module control of this pin if (!direct_table[P1_21_PWM_channel - 1].assigned) return false;
map_MR[P1_21_PWM_channel - 1].PINSEL_reg = &LPC_PINCON->PINSEL3; LPC_PWM1->PCR |= _BV(8 + P1_21_PWM_channel); // enable PWM1 module control of this pin
map_MR[P1_21_PWM_channel - 1].PINSEL_bits = 0x2 << 10; // ISR must do this AFTER setting PCR LPC_PINCON->PINSEL3 |= 0x2 << 10; // must set pin function AFTER setting PCR
break; // load the new time value
LPC_PWM1->MR3 = MAX(MIN(value, direct_table[P1_21_PWM_channel - 1].max), direct_table[P1_21_PWM_channel - 1].min);
LPC_PWM1->LER = 0x1 << P1_21_PWM_channel; // Set the latch Enable Bit to load the new Match Value on the next MR0
return true;
case P1_18: // Servo 3, PWM1 channel 1 (Pin 4 P1.18 PWM1.1) case P1_18: // Servo 3, PWM1 channel 1 (Pin 4 P1.18 PWM1.1)
map_MR[P1_18_PWM_channel - 1].PCR_bit = _BV(8 + P1_18_PWM_channel); // enable PWM1 module control of this pin if (!direct_table[P1_18_PWM_channel - 1].assigned) return false;
map_MR[P1_18_PWM_channel - 1].PINSEL_reg = &LPC_PINCON->PINSEL3; LPC_PWM1->PCR |= _BV(8 + P1_18_PWM_channel); // enable PWM1 module control of this pin
map_MR[P1_18_PWM_channel - 1].PINSEL_bits = 0x2 << 4; // ISR must do this AFTER setting PCR LPC_PINCON->PINSEL3 |= 0x2 << 4; // must set pin function AFTER setting PCR
break; // load the new time value
LPC_PWM1->MR1 = MAX(MIN(value, direct_table[P1_18_PWM_channel - 1].max), direct_table[P1_18_PWM_channel - 1].min);
LPC_PWM1->LER = 0x1 << P1_18_PWM_channel; // Set the latch Enable Bit to load the new Match Value on the next MR0
return true;
case P2_04: // D9 FET, PWM1 channel 5 (Pin 9 P2_04 PWM1.5) case P2_04: // D9 FET, PWM1 channel 5 (Pin 9 P2_04 PWM1.5)
map_MR[P2_04_PWM_channel - 1].PCR_bit = _BV(8 + P2_04_PWM_channel); // enable PWM1 module control of this pin if (!direct_table[P2_04_PWM_channel - 1].assigned) return false;
map_MR[P2_04_PWM_channel - 1].PINSEL_reg = &LPC_PINCON->PINSEL4; LPC_PWM1->PCR |= _BV(8 + P2_04_PWM_channel); // enable PWM1 module control of this pin
map_MR[P2_04_PWM_channel - 1].PINSEL_bits = 0x1 << 8; // ISR must do this AFTER setting PCR LPC_PINCON->PINSEL4 |= 0x1 << 8; // must set pin function AFTER setting PCR
break; // load the new time value
LPC_PWM1->MR5 = MAX(MIN(value, direct_table[P2_04_PWM_channel - 1].max), direct_table[P2_04_PWM_channel - 1].min);
LPC_PWM1->LER = 0x1 << P2_04_PWM_channel; // Set the latch Enable Bit to load the new Match Value on the next MR0
return true;
case P2_05: // D10 FET, PWM1 channel 6 (Pin 10 P2_05 PWM1.6) case P2_05: // D10 FET, PWM1 channel 6 (Pin 10 P2_05 PWM1.6)
map_MR[P2_05_PWM_channel - 1].PCR_bit = _BV(8 + P2_05_PWM_channel); // enable PWM1 module control of this pin if (!direct_table[P2_05_PWM_channel - 1].assigned) return false;
map_MR[P2_05_PWM_channel - 1].PINSEL_reg = &LPC_PINCON->PINSEL4; LPC_PWM1->PCR |= _BV(8 + P2_05_PWM_channel); // enable PWM1 module control of this pin
map_MR[P2_05_PWM_channel - 1].PINSEL_bits = 0x1 << 10; // ISR must do this AFTER setting PCR LPC_PINCON->PINSEL4 |= 0x1 << 10; // must set pin function AFTER setting PCR
break; // load the new time value
default: // ISR pins LPC_PWM1->MR6 = MAX(MIN(value, direct_table[P2_05_PWM_channel - 1].max), direct_table[P2_05_PWM_channel - 1].min);
pinMode(pin, OUTPUT); // set pin to output LPC_PWM1->LER = 0x1 << P2_05_PWM_channel; // Set the latch Enable Bit to load the new Match Value on the next MR0
break; return true;
} }
ISR_table[slot].microseconds = MAX(MIN(value, ISR_table[slot].max), ISR_table[slot].min); //// interrupt controlled PWM code
ISR_table[slot].active_flag = 1; NVIC_DisableIRQ(HAL_PWM_TIMER_IRQn);
if (!ISR_table_update) // use the most up to date table
ISR_table_update = true; COPY_ACTIVE_TABLE; // copy active table into work table
NVIC_EnableIRQ(PWM1_IRQn); // re-enable PWM interrupts
return 1;
}
uint8_t slot = 0xFF;
uint32_t LPC1768_PWM_interrupt_mask = 1; for (uint8_t i = 0; i < NUM_ISR_PWMS; i++) // find slot
if (work_table[i].pin == pin) { slot = i; break; }
if (slot == 0xFF) { // return error if pin not found
void LPC1768_PWM_update(void) { // only called by the ISR NVIC_EnableIRQ(HAL_PWM_TIMER_IRQn);
LPC1768_PWM_interrupt_mask = 0; // set match registers to new values, build IRQ mask return false;
// first setup directly controlled PWM pin slots
bool found;
for (uint8_t i = 0; i < NUM_PWMS; i++) {
ISR_table[i].PCR_bit = 0; // clear entries
ISR_table[i].PINSEL_reg = 0;
ISR_table[i].PINSEL_bits = 0;
ISR_table[i].PWM_flag = 1; // mark slot as interrupt mode until find differently
if (ISR_table[i].active_flag) {
ISR_table[i].sequence = i + 1;
// first see if there is a PWM1 controlled pin for this entry
found = false;
for (uint8_t j = 0; (j < NUM_PWMS) && !found; j++) {
if ( (map_MR[j].map_PWM_PIN == ISR_table[i].pin)) {
map_MR[j].map_PWM_INT = 1; // flag that it's already setup for direct control
ISR_table[i].PWM_mask = 0;
ISR_table[i].PCR_bit = map_MR[j].PCR_bit; // PCR register bit to enable PWM1 control of this pin
ISR_table[i].PINSEL_reg = map_MR[j].PINSEL_reg; // PINSEL register address to set pin mode to PWM1 control} MR_map;
ISR_table[i].PINSEL_bits = map_MR[j].PINSEL_bits; // PINSEL register bits to set pin mode to PWM1 control} MR_map;
map_MR[j].map_used = 2;
ISR_table[i].PWM_flag = 0;
*map_MR[j].MR_register = ISR_table[i].microseconds;
found = true;
}
}
}
else
ISR_table[i].sequence = 0;
} }
// next fill in interrupt slots work_table[slot].microseconds = MAX(MIN(value, work_table[slot].max), work_table[slot].min);;
for (uint8_t i = 0; i < NUM_PWMS; i++) { work_table[slot].active_flag = true;
if (ISR_table[i].active_flag && ISR_table[i].PWM_flag) {
// setup interrupt slot
found = false;
for (uint8_t k = 0; (k < NUM_PWMS) && !found; k++) {
if ( !(map_MR[k].map_PWM_INT || map_MR[k].map_used)) {
*map_MR[k].MR_register = ISR_table[i].microseconds; // found one for an interrupt pin
map_MR[k].map_used = 1;
LPC1768_PWM_interrupt_mask |= _BV(3 * (k + 1)); // set bit in the MCR to enable this MR to generate an interrupt
ISR_table[i].set_register = PIN_IS_INVERTED(ISR_table[i].pin) ? &LPC_GPIO(LPC1768_PIN_PORT(ISR_table[i].pin))->FIOCLR : &LPC_GPIO(LPC1768_PIN_PORT(ISR_table[i].pin))->FIOSET;
ISR_table[i].clr_register = PIN_IS_INVERTED(ISR_table[i].pin) ? &LPC_GPIO(LPC1768_PIN_PORT(ISR_table[i].pin))->FIOSET : &LPC_GPIO(LPC1768_PIN_PORT(ISR_table[i].pin))->FIOCLR;
ISR_table[i].write_mask = LPC_PIN(LPC1768_PIN_PIN(ISR_table[i].pin));
ISR_table[i].PWM_mask = _BV(IR_BIT(k + 1)); // bit in the IR that will go active when this MR generates an interrupt
ISR_table[i].PWM_flag = 1;
found = true;
}
}
}
}
LPC1768_PWM_interrupt_mask |= (uint32_t) _BV(0); // add in MR0 interrupt LPC1768_PWM_sort(); // sort table by microseconds
ISR_table_update = true;
LPC_PWM1->LER = 0x07E; // Set the latch Enable Bits to load the new Match Values for MR1 - MR6 NVIC_EnableIRQ(HAL_PWM_TIMER_IRQn); // re-enable PWM interrupts
return 1;
} }
@ -469,97 +450,102 @@ bool useable_hardware_PWM(pin_t pin) {
pin = GET_PIN_MAP_PIN(GET_PIN_MAP_INDEX(pin & 0xFF)); pin = GET_PIN_MAP_PIN(GET_PIN_MAP_INDEX(pin & 0xFF));
NVIC_DisableIRQ(PWM1_IRQn); NVIC_DisableIRQ(HAL_PWM_TIMER_IRQn);
bool return_flag = false; bool return_flag = false;
for (uint8_t i = 0; i < NUM_PWMS; i++) // see if it's already setup for (uint8_t i = 0; i < NUM_ISR_PWMS; i++) // see if it's already setup
if (ISR_table[i].pin == pin && ISR_table[i].sequence) return_flag = true; if (active_table[i].pin == pin) return_flag = true;
for (uint8_t i = 0; i < NUM_PWMS; i++) // see if there is an empty slot for (uint8_t i = 0; i < NUM_ISR_PWMS; i++) // see if there is an empty slot
if (!ISR_table[i].sequence) return_flag = true; if (!active_table[i].set_register) return_flag = true;
NVIC_EnableIRQ(PWM1_IRQn); // re-enable PWM interrupts NVIC_EnableIRQ(HAL_PWM_TIMER_IRQn); // re-enable PWM interrupts
return return_flag; return return_flag;
} }
//////////////////////////////////////////////////////////////////////////////// ////////////////////////////////////////////////////////////////////////////////
#define HAL_PWM_LPC1768_ISR extern "C" void PWM1_IRQHandler(void)
// Both loops could be terminated when the last active channel is found but that would #define PWM_LPC1768_ISR_SAFETY_FACTOR 5 // amount of time needed to guarantee MR1 count will be above TC
// result in variations ISR run time which results in variations in pulse width volatile bool in_PWM_isr = false;
/** HAL_PWM_TIMER_ISR {
* Changes to PINSEL, PCR and MCR are only done during the MR0 interrupt otherwise bool first_active_entry = true;
* the wrong pin may be toggled or even have the system hang. uint32_t next_MR1_val;
*/
if (in_PWM_isr) goto exit_PWM_ISR; // prevent re-entering this ISR
in_PWM_isr = true;
HAL_PWM_LPC1768_ISR { if (HAL_PWM_TIMER->IR & 0x01) { // MR0 interrupt
next_MR1_val = first_MR1_value; // only used if have a blank ISR table
if (LPC_PWM1->IR & 0x1) { // MR0 interrupt if (ISR_table_update) { // new values have been loaded so swap tables
if (ISR_table_update) { // new values have been loaded so set everything temp_table = active_table;
LPC1768_PWM_update(); // update & swap table active_table = work_table;
LPC_PWM1->MCR = LPC1768_PWM_interrupt_mask; // enable new PWM individual channel interrupts work_table = temp_table;
ISR_table_update = false;
} }
for (uint8_t i = 0; i < NUM_PWMS; i++) { }
if (ISR_table[i].active_flag && !((ISR_table[i].pin == P1_20) || HAL_PWM_TIMER->IR = 0x3F; // clear all interrupts
(ISR_table[i].pin == P1_21) ||
(ISR_table[i].pin == P1_18) || for (uint8_t i = 0; i < NUM_ISR_PWMS; i++) {
(ISR_table[i].pin == P2_04) || if (active_table[i].active_flag) {
(ISR_table[i].pin == P2_05)) if (first_active_entry) {
) { first_active_entry = false;
*ISR_table[i].set_register = ISR_table[i].write_mask; // set pins for all enabled interrupt channels active next_MR1_val = active_table[i].microseconds;
} }
if (ISR_table_update && ISR_table[i].PCR_bit) { if (HAL_PWM_TIMER->TC < active_table[i].microseconds) {
LPC_PWM1->PCR |= ISR_table[i].PCR_bit; // enable PWM1 module control of this pin *active_table[i].set_register = active_table[i].write_mask; // set pin high
*ISR_table[i].PINSEL_reg |= ISR_table[i].PINSEL_bits; // set pin mode to PWM1 control - must be done after PCR
} }
} else {
ISR_table_update = false; *active_table[i].clr_register = active_table[i].write_mask; // set pin low
LPC_PWM1->IR = 0x01; // clear the MR0 interrupt flag bit next_MR1_val = (i == NUM_ISR_PWMS -1)
} ? LPC_PWM1_MR0 + 1 // done with table, wait for MR0
else { : active_table[i + 1].microseconds; // set next MR1 interrupt?
for (uint8_t i = 0; i < NUM_PWMS; i++)
if (ISR_table[i].active_flag && (LPC_PWM1->IR & ISR_table[i].PWM_mask)) {
LPC_PWM1->IR = ISR_table[i].PWM_mask; // clear the interrupt flag bits for expected interrupts
*ISR_table[i].clr_register = ISR_table[i].write_mask; // set channel to inactive
} }
}
} }
if (first_active_entry) next_MR1_val = LPC_PWM1_MR0 + 1; // empty table so disable MR1 interrupt
LPC_PWM1->IR = 0x70F; // guarantees all interrupt flags are cleared which, if there is an unexpected HAL_PWM_TIMER->MR1 = MAX(next_MR1_val, HAL_PWM_TIMER->TC + PWM_LPC1768_ISR_SAFETY_FACTOR); // set next
// PWM interrupt, will keep the ISR from hanging which will crash the controller in_PWM_isr = false;
exit_PWM_ISR:
return;
} }
#endif #endif
///////////////////////////////////////////////////////////////// /////////////////////////////////////////////////////////////////
///////////////// HARDWARE FIRMWARE INTERACTION //////////////// ///////////////// HARDWARE FIRMWARE INTERACTION ////////////////
///////////////////////////////////////////////////////////////// /////////////////////////////////////////////////////////////////
/** /**
* Almost all changes to the hardware registers must be coordinated with the Match Register 0 (MR0) * There are two distinct systems used for PWMs:
* interrupt. The only exception is detaching pins. It doesn't matter when they go * directly controlled pins
* tristate. * ISR controlled pins.
* *
* The LPC1768_PWM_init routine kicks off the MR0 interrupt. This interrupt is never disabled. It * The two systems are independent of each other. The use the same counter frequency so there's no
* can be delayed by higher priority interrupts. Actions on directly controlled pins are not delayed * translation needed when setting the time values. The init, attach, detach and write routines all
* by other interrupts * start with the direct pin code which is followed by the ISR pin code.
* *
* The ISR_table_update flag is set when the ISR table needs to be rebuilt. It is * The PMW1 module handles the directly controlled pins. Each directly controlled pin is associated
* cleared by the ISR during the MR0 interrupt after it rebuilds the ISR table. * with a match register (MR1 - MR6). When the associated MR equals the module's TIMER/COUNTER (TC)
* then the pins is set to low. The MR0 register controls the repetition rate. When the TC equals
* MR0 then the TC is reset and ALL directly controlled pins are set high. The resulting pulse widths
* are almost immune to system loading and ISRs. No PWM1 interrupts are used.
* *
* The sequence of events during a write to a PWM channel is: * The ISR controlled pins use the TIMER/COUNTER, MR0 and MR1 registers from one timer. MR0 controls
* 1) Attach routine puts the pin number in the ISR table but doesn't mark it active. * period of the controls the repetition rate. When the TC equals MR0 then the TC is reset and an
* 2) Write routine marks the pin as active, updates the helper table and flags the ISR that the * interrupt is generated. When the TC equals MR1 then an interrupt is generated.
* ISR table needs to be rebuilt.
* 3) On the MR0 interrupt the ISR:
* a. Rebuilds the ISR table if needed.
* MR1-MR6 are updated at this time. The updates aren't put into use until the first
* MR0 after the LER register has been written. The LER register is written during the
* table rebuild process. The result is new timing takes 20-40 mS to be implemented.
* b. Sets the interrupt controlled pin(s) to their active state
* c. Writes to the PCR register to enable the directly controlled pins
* d. Sets the PINSEL register to the function/mode for the directly controlled pins
* *
* 4) For each interrupt controlled pin there is another ISR call. During this call the pin is set * Each interrupt does the following:
* to its inactive state. The call is initiated when a MR1-MR6 reg times out. * 1) Swaps the tables if it's a MR0 interrupt and the swap flag is set. It then clears the swap flag.
* 2) Scans the entire ISR table (it's been sorted low to high time)
* a. If its the first active entry then it grabs the time as a tentative time for MR1
* b. If active and TC is less than the time then it sets the pin high
* c. If active and TC is more than the time it sets the pin high
* d. On every entry that sets a pin low it grabs the NEXT entry's time for use as the next MR1.
* This results in MR1 being set to the time in the first active entry that does NOT set a
* pin low.
* e. If it's setting the last entry's pin low then it sets MR1 to a value bigger than MR0
* f. If no value has been grabbed for the next MR1 then it's an empty table and MR1 is set to a
* value greater than MR0
*/ */

4
Marlin/src/HAL/HAL_LPC1768/arduino.cpp
Unescape Escape View File

@ -136,8 +136,8 @@ void analogWrite(pin_t pin, int pwm_value) { // 1 - 254: pwm_value, 0: LOW, 255
digitalWrite(pin, value); digitalWrite(pin, value);
} }
else { else {
if (LPC1768_PWM_attach_pin(pin, 1, (LPC_PWM1->MR0 - MR0_MARGIN), 0xff)) // locks up if get too close to MR0 value if (LPC1768_PWM_attach_pin(pin, 1, LPC_PWM1->MR0, 0xff))
LPC1768_PWM_write(pin, map(value, 1, 254, 1, (LPC_PWM1->MR0 - MR0_MARGIN))); // map 1-254 onto PWM range LPC1768_PWM_write(pin, map(value, 0, 255, 1, LPC_PWM1->MR0)); // map 1-254 onto PWM range
else { // out of PWM channels else { // out of PWM channels
if (!out_of_PWM_slots) MYSERIAL.printf(".\nWARNING - OUT OF PWM CHANNELS\n.\n"); //only warn once if (!out_of_PWM_slots) MYSERIAL.printf(".\nWARNING - OUT OF PWM CHANNELS\n.\n"); //only warn once
out_of_PWM_slots = true; out_of_PWM_slots = true;

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