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zynq-rs
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pca954x: fix to work on cold boot

This commit is contained in:
mwojcik 2022-02-09 17:23:33 +08:00
parent bc41b91192
commit 14b0247716
2 changed files with 15 additions and 17 deletions
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30
libboard_zynq/src/i2c/mod.rs
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@ -144,27 +144,26 @@ impl I2c {
}
#[cfg(feature = "target_kasli_soc")]
fn pca_autodetect(&mut self) -> Result<PCA954X, &'static str> {
pub fn pca_autodetect(&mut self) -> Result<PCA954X, &'static str> {
// start with resetting the PCA954X
self.i2cswr_oe(false);
self.i2cswr_o(false);
self.delay_us(10); // reset time is just 500ns
self.i2cswr_oe(true);
self.i2cswr_o(true);
self.delay_us(10);
let pca954x_addr = 0x71;
/*self.i2cswr_oe(false);
self.unit_delay();
self.i2cswr_oe(true);*/
let pca954x_read_addr = (0x71 << 1) | 0x01;
self.start()?;
// read the config register
if !self.write(pca954x_addr)? {
if !self.write(pca954x_read_addr)? {
return Err("PCA954X failed to ack read address");
}
let config = self.read(true)?;
let config = self.read(false)?;
let pca = match config {
0x00 => PCA954X::PCA9548,
0x08 => PCA954X::PCA9547,
_ => { return Err("Unknown PCA954X type."); }
_ => { return Err("Unknown response for PCA954X autodetect")},
};
self.stop()?;
Ok(pca)
@ -196,14 +195,13 @@ impl I2c {
return Err("SCL is stuck low");
}
// postcondition: SCL and SDA high
#[cfg(feature = "target_kasli_soc")]
{
self.unit_delay();
self.pca_type = self.pca_autodetect()?;
}
#[cfg(not(feature = "target_kasli_soc"))]
{
self.pca_type = PCA954X::PCA9548;
}
Ok(())
}
@ -287,7 +285,7 @@ impl I2c {
if self.sda_i() { data |= 1 << bit }
self.scl_oe(true);
}
// Send ack/nack
// Send ack/nack (true = nack, false = ack)
self.sda_oe(ack);
self.unit_delay();
self.scl_oe(false);