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[LPC11U68, LPC1549] Fixed PwmOut SCT Bugs #1587

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Merged
merged 2 commits into from
Mar 5, 2016
Merged

[LPC11U68, LPC1549] Fixed PwmOut SCT Bugs #1587

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792b359
[LPC11U68, LPC1549] Fixed PwmOut SCT Bugs
neilt6 Mar 3, 2016
b3e2763
[LPC11U68, LPC1549] Improved PwmOut Documentation
neilt6 Mar 4, 2016
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35 changes: 29 additions & 6 deletions libraries/mbed/targets/hal/TARGET_NXP/TARGET_LPC11U6X/pwmout_api.c
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Original file line number Diff line number Diff line change
Expand Up @@ -137,16 +137,23 @@ void pwmout_write(pwmout_t* obj, float value) {
uint32_t t_on = (uint32_t)((float)(pwm->MATCHREL0 + 1) * value);
if (t_on > 0) {
pwm->MATCHREL1 = t_on - 1;
pwm->CTRL &= ~(1 << 2);

// Un-halt the timer and ensure the new pulse-width takes immediate effect if necessary
if (pwm->CTRL & (1 << 2)) {
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might be good to add a comment here what this if () handles?

pwm->MATCH1 = pwm->MATCHREL1;
pwm->CTRL &= ~(1 << 2);
}
} else {
// Halt the timer and force the output low
pwm->CTRL |= (1 << 2) | (1 << 3);
pwm->OUTPUT = 0x00000000;
}
}

float pwmout_read(pwmout_t* obj) {
uint32_t t_off = obj->pwm->MATCHREL0 + 1;
uint32_t t_on = obj->pwm->MATCHREL1 + 1;
LPC_SCT0_Type* pwm = obj->pwm;
uint32_t t_off = pwm->MATCHREL0 + 1;
uint32_t t_on = (!(pwm->CTRL & (1 << 2))) ? pwm->MATCHREL1 + 1 : 0;
float v = (float)t_on/(float)t_off;
return (v > 1.0f) ? (1.0f) : (v);
}
Expand All @@ -163,17 +170,27 @@ void pwmout_period_ms(pwmout_t* obj, int ms) {
void pwmout_period_us(pwmout_t* obj, int us) {
LPC_SCT0_Type* pwm = obj->pwm;
uint32_t t_off = pwm->MATCHREL0 + 1;
uint32_t t_on = pwm->MATCHREL1 + 1;
uint32_t t_on = (!(pwm->CTRL & (1 << 2))) ? pwm->MATCHREL1 + 1 : 0;
float v = (float)t_on/(float)t_off;
uint32_t period_ticks = (uint32_t)(((uint64_t)SystemCoreClock * (uint64_t)us) / (uint64_t)1000000);
uint32_t pulsewidth_ticks = period_ticks * v;
pwm->MATCHREL0 = period_ticks - 1;
if (pulsewidth_ticks > 0) {
pwm->MATCHREL1 = pulsewidth_ticks - 1;
pwm->CTRL &= ~(1 << 2);

// Un-halt the timer and ensure the new period & pulse-width take immediate effect if necessary
if (pwm->CTRL & (1 << 2)) {
pwm->MATCH0 = pwm->MATCHREL0;
pwm->MATCH1 = pwm->MATCHREL1;
pwm->CTRL &= ~(1 << 2);
}
} else {
// Halt the timer and force the output low
pwm->CTRL |= (1 << 2) | (1 << 3);
pwm->OUTPUT = 0x00000000;

// Ensure the new period will take immediate effect when the timer is un-halted
pwm->MATCH0 = pwm->MATCHREL0;
}
}

Expand All @@ -189,8 +206,14 @@ void pwmout_pulsewidth_us(pwmout_t* obj, int us) {
LPC_SCT0_Type* pwm = obj->pwm;
if (us > 0) {
pwm->MATCHREL1 = (uint32_t)(((uint64_t)SystemCoreClock * (uint64_t)us) / (uint64_t)1000000) - 1;
pwm->CTRL &= ~(1 << 2);

// Un-halt the timer and ensure the new pulse-width takes immediate effect if necessary
if (pwm->CTRL & (1 << 2)) {
pwm->MATCH1 = pwm->MATCHREL1;
pwm->CTRL &= ~(1 << 2);
}
} else {
// Halt the timer and force the output low
pwm->CTRL |= (1 << 2) | (1 << 3);
pwm->OUTPUT = 0x00000000;
}
Expand Down
35 changes: 29 additions & 6 deletions libraries/mbed/targets/hal/TARGET_NXP/TARGET_LPC15XX/pwmout_api.c
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Original file line number Diff line number Diff line change
Expand Up @@ -118,16 +118,23 @@ void pwmout_write(pwmout_t* obj, float value) {
uint32_t t_on = (uint32_t)((float)(pwm->MATCHREL0 + 1) * value);
if (t_on > 0) {
pwm->MATCHREL1 = t_on - 1;
pwm->CTRL &= ~(1 << 2);

// Un-halt the timer and ensure the new pulse-width takes immediate effect if necessary
if (pwm->CTRL & (1 << 2)) {
pwm->MATCH1 = pwm->MATCHREL1;
pwm->CTRL &= ~(1 << 2);
}
} else {
// Halt the timer and force the output low
pwm->CTRL |= (1 << 2) | (1 << 3);
pwm->OUTPUT = 0x00000000;
}
}

float pwmout_read(pwmout_t* obj) {
uint32_t t_off = obj->pwm->MATCHREL0 + 1;
uint32_t t_on = obj->pwm->MATCHREL1 + 1;
LPC_SCT0_Type* pwm = obj->pwm;
uint32_t t_off = pwm->MATCHREL0 + 1;
uint32_t t_on = (!(pwm->CTRL & (1 << 2))) ? pwm->MATCHREL1 + 1 : 0;
float v = (float)t_on/(float)t_off;
return (v > 1.0f) ? (1.0f) : (v);
}
Expand All @@ -144,17 +151,27 @@ void pwmout_period_ms(pwmout_t* obj, int ms) {
void pwmout_period_us(pwmout_t* obj, int us) {
LPC_SCT0_Type* pwm = obj->pwm;
uint32_t t_off = pwm->MATCHREL0 + 1;
uint32_t t_on = pwm->MATCHREL1 + 1;
uint32_t t_on = (!(pwm->CTRL & (1 << 2))) ? pwm->MATCHREL1 + 1 : 0;
float v = (float)t_on/(float)t_off;
uint32_t period_ticks = (uint32_t)(((uint64_t)SystemCoreClock * (uint64_t)us) / (uint64_t)1000000);
uint32_t pulsewidth_ticks = period_ticks * v;
pwm->MATCHREL0 = period_ticks - 1;
if (pulsewidth_ticks > 0) {
pwm->MATCHREL1 = pulsewidth_ticks - 1;
pwm->CTRL &= ~(1 << 2);

// Un-halt the timer and ensure the new period & pulse-width take immediate effect if necessary
if (pwm->CTRL & (1 << 2)) {
pwm->MATCH0 = pwm->MATCHREL0;
pwm->MATCH1 = pwm->MATCHREL1;
pwm->CTRL &= ~(1 << 2);
}
} else {
// Halt the timer and force the output low
pwm->CTRL |= (1 << 2) | (1 << 3);
pwm->OUTPUT = 0x00000000;

// Ensure the new period will take immediate effect when the timer is un-halted
pwm->MATCH0 = pwm->MATCHREL0;
}
}

Expand All @@ -170,8 +187,14 @@ void pwmout_pulsewidth_us(pwmout_t* obj, int us) {
LPC_SCT0_Type* pwm = obj->pwm;
if (us > 0) {
pwm->MATCHREL1 = (uint32_t)(((uint64_t)SystemCoreClock * (uint64_t)us) / (uint64_t)1000000) - 1;
pwm->CTRL &= ~(1 << 2);

// Un-halt the timer and ensure the new pulse-width takes immediate effect if necessary
if (pwm->CTRL & (1 << 2)) {
pwm->MATCH1 = pwm->MATCHREL1;
pwm->CTRL &= ~(1 << 2);
}
} else {
// Halt the timer and force the output low
pwm->CTRL |= (1 << 2) | (1 << 3);
pwm->OUTPUT = 0x00000000;
}
Expand Down