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fw: i2c progress, writing works (???)

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This commit is contained in:
David Lenfesty 2023-06-17 21:31:50 +00:00
parent 349fe96b0d
commit c642bd72cb
2 changed files with 70 additions and 60 deletions
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99
firmware/src/i2c.rs
View File

@ -2,8 +2,7 @@
//!
//! See `gateware/i2c.py` for register information
use crate::timer::busy_wait_us;
use crate::{read_reg, write_reg};
use crate::{read_reg, write_reg, timer::busy_wait_us};
use core::arch::asm;
use embedded_hal::blocking::i2c::{Operation, Read, SevenBitAddress, Transactional, Write};
@ -33,25 +32,39 @@ use core::fmt::Write as _;
impl LitexI2c {
pub fn new(base_addr: u32) -> Self {
LitexI2c { base_addr }
let mut device = LitexI2c { base_addr };
device.set_scl(true);
device.set_sda(true);
device.set_oe(true);
device
}
fn set_scl(&mut self, val: u32) {
fn set_reg(&mut self, offset: u32, set: bool) {
static mut reg_state: u32 = 0;
unsafe {
write_reg(self.base_addr + REG_W, (val & 0x01) << FIELD_W_SCL);
if set {
reg_state |= (1 << offset);
} else {
reg_state &= !(1 << offset);
}
write_reg(self.base_addr + REG_W, reg_state);
}
}
fn set_sda(&mut self, val: u32) {
unsafe {
write_reg(self.base_addr + REG_W, (val & 0x01) << FIELD_W_SDA);
}
fn set_scl(&mut self, set: bool) {
defmt::debug!("set scl {}", set);
self.set_reg(FIELD_W_SCL, set);
}
fn set_oe(&mut self, val: u32) {
unsafe {
write_reg(self.base_addr + REG_W, (val & 0x01) << FIELD_W_OE);
}
fn set_sda(&mut self, set: bool) {
self.set_reg(FIELD_W_SDA, set);
}
fn set_oe(&mut self, set: bool) {
self.set_reg(FIELD_W_OE, set);
}
fn get_sda(&mut self) -> u8 {
@ -63,12 +76,11 @@ impl LitexI2c {
///
/// Assumes SCL and SDA have been high due to bus inactivity
unsafe fn start(&mut self) {
self.set_oe(1);
self.set_scl(1);
self.set_sda(1);
self.set_scl(true);
self.set_sda(true);
busy_wait_us(WAIT_PERIOD_US);
self.set_sda(0);
self.set_sda(false);
busy_wait_us(WAIT_PERIOD_US);
}
@ -76,16 +88,15 @@ impl LitexI2c {
///
/// Assumes it was called after an ACK bit
unsafe fn repeated_start(&mut self) {
self.set_scl(0);
self.set_sda(1);
self.set_oe(1);
self.set_scl(false);
self.set_sda(true);
busy_wait_us(WAIT_PERIOD_US);
self.set_scl(1);
self.set_scl(true);
busy_wait_us(WAIT_PERIOD_US);
// TODO does this third half-clock break timing?
self.set_sda(0);
self.set_sda(false);
busy_wait_us(WAIT_PERIOD_US);
}
@ -93,49 +104,44 @@ impl LitexI2c {
///
/// Assumes it was called after an ACK bit
unsafe fn stop(&mut self) {
self.set_scl(0);
self.set_sda(0);
self.set_oe(1);
self.set_scl(false);
self.set_sda(false);
busy_wait_us(WAIT_PERIOD_US);
self.set_scl(1);
self.set_scl(true);
busy_wait_us(WAIT_PERIOD_US);
// TODO does this third half-clock break timing?
//self.set_oe(0); // Disable and let pullup take bus high
self.set_sda(1);
//self.set_oe(false); // Disable and let pullup take bus high
self.set_sda(true);
busy_wait_us(WAIT_PERIOD_US);
}
unsafe fn write_byte(&mut self, byte: u8) {
self.set_oe(1); // Take SDA to write data out
for i in 0..8 {
// Write data out before we clock high
self.set_scl(0);
self.set_scl(false);
busy_wait_us(WAIT_PERIOD_US);
// Clock data in
self.set_scl(1);
self.set_sda(byte as u32 >> (7 - i));
self.set_sda((byte >> (7 - i)) & 0x01 != 0);
self.set_scl(true);
busy_wait_us(WAIT_PERIOD_US)
}
}
unsafe fn read_byte(&mut self) -> u8 {
self.set_oe(0); // De-assert to read data
let mut out = 0;
for i in 0..8 {
self.set_scl(0);
self.set_scl(false);
busy_wait_us(WAIT_PERIOD_US);
self.set_scl(1);
self.set_scl(true);
busy_wait_us(WAIT_PERIOD_US);
// TODO sampling at the end of the clock may not work 100% of the time
// ideally should sample in the middle
out |= (self.get_sda() << 7 - i);
out |= (self.get_sda() << (7 - i));
}
out
@ -143,24 +149,22 @@ impl LitexI2c {
// Returns if there was an ACK
unsafe fn get_ack(&mut self) -> bool {
self.set_oe(0); // Release SDA to read ACK
self.set_sda(1);
self.set_scl(0);
self.set_scl(false);
self.set_sda(true);
busy_wait_us(WAIT_PERIOD_US);
self.set_scl(1);
self.set_scl(true);
busy_wait_us(WAIT_PERIOD_US);
self.get_sda() == 0
}
unsafe fn set_ack(&mut self, ack: bool) {
self.set_oe(1); // Take SDA
self.set_sda(!ack as u32);
self.set_scl(0);
self.set_scl(false);
busy_wait_us(WAIT_PERIOD_US);
self.set_scl(1);
self.set_sda(!ack);
self.set_scl(true);
busy_wait_us(WAIT_PERIOD_US);
}
}
@ -176,13 +180,16 @@ impl Write<SevenBitAddress> for LitexI2c {
// Write address and write bit
self.write_byte((address << 1) | 0);
if !self.get_ack() {
defmt::debug!("write addr fail");
self.stop();
return Err(Error::Nack);
}
for b in bytes {
self.write_byte(*b);
defmt::debug!("write data ");
if !self.get_ack() {
defmt::debug!("write data fail");
self.stop();
return Err(Error::Nack);
}

31
firmware/src/main.rs
View File

@ -139,7 +139,8 @@ fn main() -> ! {
match dac.write_config(
&mut i2c,
mcp4726::Config {
vref_source: mcp4726::VRef::UnbufferedVRef,
//vref_source: mcp4726::VRef::UnbufferedVRef,
vref_source: mcp4726::VRef::UnbufferedVDD,
operation: mcp4726::PowerDown::NormalOperation,
use_2x_gain: false,
},
@ -148,20 +149,22 @@ fn main() -> ! {
Err(_) => defmt::debug!("Write config failed"),
}
//match dac.read_status(&mut i2c) {
// Ok(status) => {
// defmt::debug!(
// "DAC status: ready: {}, powered: {}",
// status.ready,
// status.device_powered
// );
match dac.read_status(&mut i2c) {
Ok(status) => {
defmt::debug!(
"DAC status: ready: {}, powered: {}",
status.ready,
status.device_powered
);
// if sock.can_send() {
// write!(sock, "DAC: ready: {}, powered: {}", status.ready, status.device_powered);
// }
// }
// Err(_) => defmt::debug!("Error reading from DAC"),
//};
if sock.can_send() {
write!(sock, "DAC: ready: {}, powered: {}", status.ready, status.device_powered);
}
}
Err(_) => defmt::debug!("Error reading from DAC"),
};
dac.write_dac(&mut i2c, 800);
//if toggle {
// sampler::clear_buffers();