55 lines
1.5 KiB
Rust
55 lines
1.5 KiB
Rust
use crate::device::sys_timer::sleep;
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use fugit::MegahertzU32;
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use stm32f4xx_hal::{
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hal::{spi::SpiBus, digital::OutputPin},
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spi,
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};
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pub const SPI_MODE: spi::Mode = spi::Mode {
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polarity: spi::Polarity::IdleLow,
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phase: spi::Phase::CaptureOnFirstTransition,
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};
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// MAX5719 Max Frequency: 50MHz | SPI2 Max Frequency: 21MHz
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pub const SPI_CLOCK_MHZ: MegahertzU32 = MegahertzU32::from_raw(21);
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pub const MAX_VALUE: u32 = 0xFFFFF;
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pub struct Dac<SPI: SpiBus<u8>, S1: OutputPin, S2:OutputPin> {
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spi: SPI,
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cs_n: S1,
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load_n: S2,
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}
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impl<SPI: SpiBus<u8>, S1: OutputPin, S2: OutputPin> Dac<SPI, S1, S2> {
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pub fn new(spi: SPI, mut cs_n: S1, mut load_n: S2) -> Self {
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let _ = cs_n.set_high();
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let _ = load_n.set_high();
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Dac { spi, cs_n, load_n}
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}
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fn write(&mut self, buf: &mut [u8]) -> Result<(), SPI::Error> {
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let _ = self.cs_n.set_low();
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self.spi.write(buf)?;
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let _ = self.cs_n.set_high();
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sleep(1);
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// must be high for >= 20 ns
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let _ = self.load_n.set_low();
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// must be low for >= 20 ns
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sleep(1);
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let _ = self.load_n.set_high();
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Ok(())
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}
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pub fn set(&mut self, value: u32) -> Result<u32, SPI::Error> {
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let value = value.min(MAX_VALUE) << 4;
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let mut buf = [
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((value >> 16) & 0xFF) as u8,
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((value >> 8) & 0xFF) as u8,
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((value >> 0) & 0xFF) as u8,
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];
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self.write(&mut buf)?;
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Ok(value)
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}
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}
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