ad5680: keep sync high for 1ms

This commit is contained in:
Astro 2020-05-28 20:45:42 +02:00
parent cf03613ac5
commit f9b55508dd
3 changed files with 16 additions and 7 deletions

View File

@ -6,6 +6,7 @@ use stm32f4xx_hal::{
time::MegaHertz, time::MegaHertz,
spi, spi,
}; };
use crate::timer::sleep;
/// SPI Mode 1 /// SPI Mode 1
pub const SPI_MODE: spi::Mode = spi::Mode { pub const SPI_MODE: spi::Mode = spi::Mode {
@ -33,23 +34,23 @@ impl<SPI: Transfer<u8>, S: OutputPin> Dac<SPI, S> {
} }
} }
fn write(&mut self, mut buf: [u8; 3]) -> Result<(), SPI::Error> { fn write(&mut self, buf: &mut [u8]) -> Result<(), SPI::Error> {
// pulse sync to start a new transfer. leave sync idle low // pulse sync to start a new transfer. leave sync idle low
// afterwards to save power as recommended per datasheet. // afterwards to save power as recommended per datasheet.
let _ = self.sync.set_high(); let _ = self.sync.set_high();
cortex_m::asm::nop(); // must be high for >= 33 ns
sleep(1);
let _ = self.sync.set_low(); let _ = self.sync.set_low();
self.spi.transfer(buf)?;
self.spi.transfer(&mut buf)?;
Ok(()) Ok(())
} }
pub fn set(&mut self, value: u32) -> Result<(), SPI::Error> { pub fn set(&mut self, value: u32) -> Result<(), SPI::Error> {
let buf = [ let mut buf = [
(value >> 14) as u8, (value >> 14) as u8,
(value >> 6) as u8, (value >> 6) as u8,
(value << 2) as u8, (value << 2) as u8,
]; ];
self.write(buf) self.write(&mut buf)
} }
} }

View File

@ -89,6 +89,8 @@ fn main() -> ! {
wd.start(WATCHDOG_INTERVAL.ms()); wd.start(WATCHDOG_INTERVAL.ms());
wd.feed(); wd.feed();
timer::setup(cp.SYST, clocks);
let pins = Pins::setup( let pins = Pins::setup(
clocks, dp.TIM1, dp.TIM3, clocks, dp.TIM1, dp.TIM3,
dp.GPIOA, dp.GPIOB, dp.GPIOC, dp.GPIOE, dp.GPIOF, dp.GPIOG, dp.GPIOA, dp.GPIOB, dp.GPIOC, dp.GPIOE, dp.GPIOF, dp.GPIOG,
@ -98,7 +100,6 @@ fn main() -> ! {
let mut channels = Channels::new(pins); let mut channels = Channels::new(pins);
channels.calibrate_dac_value(0); channels.calibrate_dac_value(0);
timer::setup(cp.SYST, clocks);
#[cfg(not(feature = "generate-hwaddr"))] #[cfg(not(feature = "generate-hwaddr"))]
let hwaddr = EthernetAddress(NET_HWADDR); let hwaddr = EthernetAddress(NET_HWADDR);

View File

@ -39,3 +39,10 @@ pub fn now() -> u32 {
.deref() .deref()
}) })
} }
/// block for at least `amount` milliseconds
fn sleep(amount: u32) {
use crate::timer::now;
let start = now();
while now() - start <= amount {}
}