From c9f29534d6f3fd5bcf2cee09e70667373a8dc179 Mon Sep 17 00:00:00 2001 From: huntc Date: Tue, 25 Jan 2022 16:51:24 +1100 Subject: [PATCH] Stop PWM before assigning the new sequence I had introduced a small bug in my last PR where I assigned the sequence before stopping the PWM. I now stop the PWM before doing that now. Also, corrected a math comment. --- embassy-nrf/src/pwm.rs | 4 ++-- examples/nrf/src/bin/pwm_sequence.rs | 2 +- examples/nrf/src/bin/pwm_sequence_ppi.rs | 2 +- 3 files changed, 4 insertions(+), 4 deletions(-) diff --git a/embassy-nrf/src/pwm.rs b/embassy-nrf/src/pwm.rs index 61a28283..a77cd633 100644 --- a/embassy-nrf/src/pwm.rs +++ b/embassy-nrf/src/pwm.rs @@ -149,6 +149,8 @@ impl<'d, T: Instance> SequencePwm<'d, T> { return Err(Error::SequenceTimesAtLeastOne); } + self.stop(); + let r = T::regs(); r.seq0 @@ -165,8 +167,6 @@ impl<'d, T: Instance> SequencePwm<'d, T> { .cnt .write(|w| unsafe { w.bits(sequence.len() as u32) }); - self.stop(); - r.enable.write(|w| w.enable().enabled()); // defensive before seqstart diff --git a/examples/nrf/src/bin/pwm_sequence.rs b/examples/nrf/src/bin/pwm_sequence.rs index 561bc1dd..56c865d1 100644 --- a/examples/nrf/src/bin/pwm_sequence.rs +++ b/examples/nrf/src/bin/pwm_sequence.rs @@ -18,7 +18,7 @@ async fn main(_spawner: Spawner, p: Peripherals) { let mut config = SequenceConfig::default(); config.prescaler = Prescaler::Div128; - // 1 period is 1000 * (128/16mhz = 0.000008s = 0.008ms) = 8ms + // 1 period is 1000 * (128/16mhz = 0.000008s = 0.008ms) = 8us // but say we want to hold the value for 5000ms // so we want to repeat our value as many times as necessary until 5000ms passes // want 5000/8 = 625 periods total to occur, so 624 (we get the one period for free remember) diff --git a/examples/nrf/src/bin/pwm_sequence_ppi.rs b/examples/nrf/src/bin/pwm_sequence_ppi.rs index 213ef5ed..f03c5716 100644 --- a/examples/nrf/src/bin/pwm_sequence_ppi.rs +++ b/examples/nrf/src/bin/pwm_sequence_ppi.rs @@ -20,7 +20,7 @@ async fn main(_spawner: Spawner, p: Peripherals) { let mut config = SequenceConfig::default(); config.prescaler = Prescaler::Div128; - // 1 period is 1000 * (128/16mhz = 0.000008s = 0.008ms) = 8ms + // 1 period is 1000 * (128/16mhz = 0.000008s = 0.008ms) = 8us // but say we want to hold the value for 250ms 250ms/8 = 31.25 periods // so round to 31 - 1 (we get the one period for free remember) // thus our sequence takes 5 * 250ms or 1.25 seconds