forked from M-Labs/artiq
61 lines
1.6 KiB
Rust
61 lines
1.6 KiB
Rust
use board_misoc::{csr, clock};
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const PIN_LE: u32 = 1 << 0;
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const PIN_SIN: u32 = 1 << 1;
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const PIN_CLK: u32 = 1 << 2;
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const PIN_RST_N: u32 = 1 << 3;
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const PIN_RST: u32 = PIN_RST_N;
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const CARDS: usize = 4;
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const CHANNELS: usize = 2;
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fn set_pins(card_index: usize, chan_index: usize, pins: u32) {
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let pins = pins ^ PIN_RST_N;
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let shift = (card_index * 2 + chan_index)*4;
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unsafe {
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let state = csr::allaki_atts::out_read();
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let state = state & !(0xf << shift);
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let state = state | (pins << shift);
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csr::allaki_atts::out_write(state);
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}
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clock::spin_us(100);
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}
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/// Attenuation is in units of 0.5 dB, from 0 dB (0) to 31.5 dB (63).
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pub fn program(card_index: usize, chan_index: usize, atten: u8) {
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assert!(card_index < 4 && chan_index < 2);
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info!("card {} channel {} set to {}{} dB",
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card_index, chan_index,
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atten / 2, if atten % 2 != 0 { ".5" } else { "" });
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// 0b111111 = 0dB
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// 0b111110 = 0.5dB
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// 0b111101 = 1dB
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// 0b111100 = 1.5dB
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// ...
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// 0b011111 = 16dB
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// ...
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// 0b000000 = 31.5dB
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let atten = !atten << 2;
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let set_pins = |pins| set_pins(card_index, chan_index, pins);
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set_pins(PIN_RST);
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set_pins(0);
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for n in (0..8).rev() {
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let sin = if atten & 1 << n != 0 { PIN_SIN } else { 0 };
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set_pins(sin);
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set_pins(sin | PIN_CLK);
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}
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set_pins(PIN_LE);
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}
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/// See `program`.
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pub fn program_all(atten: u8) {
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for card in 0..CARDS {
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for chan in 0..CHANNELS {
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program(card, chan, atten)
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}
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}
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}
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