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ad5680: idle low for powersaving

softspi
Astro 2020-05-16 01:18:14 +02:00
parent c53c9a289f
commit feae22b277
2 changed files with 8 additions and 5 deletions
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11
src/ad5680.rs
View File

@ -25,7 +25,7 @@ pub struct Dac<SPI: Transfer<u8>, S: OutputPin> {
impl<SPI: Transfer<u8>, S: OutputPin> Dac<SPI, S> {
pub fn new(spi: SPI, mut sync: S) -> Self {
let _ = sync.set_high();
let _ = sync.set_low();
Dac {
spi,
@ -34,11 +34,14 @@ impl<SPI: Transfer<u8>, S: OutputPin> Dac<SPI, S> {
}
fn write(&mut self, mut buf: [u8; 3]) -> Result<(), SPI::Error> {
let _ = self.sync.set_low();
let result = self.spi.transfer(&mut buf);
// pulse sync to start a new transfer. leave sync idle low
// afterwards to save power as recommended per datasheet.
let _ = self.sync.set_high();
cortex_m::asm::nop();
let _ = self.sync.set_low();
result.map(|_| ())
self.spi.transfer(&mut buf)?;
Ok(())
}
/// value: `0..0x20_000`

2
src/main.rs
View File

@ -144,7 +144,7 @@ fn main() -> ! {
let ref_adc_data = channels.read_ref_adc(channel);
let state = channels.channel_state(channel);
let _ = writeln!(
socket, "t={} raw{}=0x{:06X} ref_adc={}",
socket, "t={} raw{}=0x{:06X} ref_adc=0x{:X}",
state.adc_time, channel, adc_data,
ref_adc_data
);