crjeder / hx711_spi Goto Github PK

Is your feature request related to a problem? Please describe.
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Additional context
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Hey! I've tried connecting it to an stm32f103 ("blue pill") board and ran into a couple of issues that this patch seems to address.

First ChAGain128 seemed to be missing a 0, noticed only because initially I tried with SPI mode 0 where the MOSI (used here as a clock driver) pin was going "high" in between bytes, resulting in an extra 1/0 transition.

That said running SPI in the mode 1 seems closer to the original intention of the code (not sure about rpi though).

This PR seems to fix it for me.

See a couple of screenshots below:

SPI mode 0 (the missing 0 fix already included)

SPI mode 1

I wrote a test example for your library: https://github.com/pronvis/drawer-robot/blob/master/crates/companion/src/bin/hx711_spi_read.rs
And it reads absolutely noise:

└─ hx711_spi_read::app::hx711_read @ src/bin/hx711_spi_read.rs:135
DEBUG #26: DYMH-06 data: -221.92485
└─ hx711_spi_read::app::hx711_read @ src/bin/hx711_spi_read.rs:135
DEBUG #31: DYMH-06 data: -0.000035274
└─ hx711_spi_read::app::hx711_read @ src/bin/hx711_spi_read.rs:135
DEBUG #35: DYMH-06 data: -221.92485
└─ hx711_spi_read::app::hx711_read @ src/bin/hx711_spi_read.rs:135
DEBUG #40: DYMH-06 data: -0.000035274
└─ hx711_spi_read::app::hx711_read @ src/bin/hx711_spi_read.rs:135
DEBUG #44: DYMH-06 data: 184.93732
└─ hx711_spi_read::app::hx711_read @ src/bin/hx711_spi_read.rs:135
DEBUG #49: DYMH-06 data: 258.91226

but non-spi reader that is used here: https://github.com/pronvis/drawer-robot/blob/master/crates/companion/src/bin/hx711_read.rs
works fine. What could be wrong?
All the difference in pin connections is:
with spi:

PB13 <-> SCK
PB14 <-> DT

with non-spi:

PA7 <-> SCK
PA6 <-> DT

HX711 have two channels: A & B.
Is it possible to connect two measurment devices simultaneously and use your library?

Is your feature request related to a problem? Please describe.

I was trying to utilize the crate on ESP32-C3. The block!(hx711.read()) will always block. After digging around, I found the SDO of ESP32-C3 is always idle at HIGH and I haven't find a way to change the behavior. So I decided to use a MOSFET to hold the SDO at LOW when no data is transfered. However, the CS on ESP32-C3 is disabled after SDO pulled itself HIGH, the value I got is not correct.

Later I tried to invert the polarity of SDO with the MOSFET and change the code, it looks better now.

Describe the solution you'd like

Introduce a new feature invert-sdo, and enable it will invert the signal on SDO, allowing external inverter. For example

#[cfg(not(feature = "invert-sdo"))]
let value = 0x00;
#[cfg(feature = "invert-sdo")]
let value = 0xFF;

Describe alternatives you've considered

Maybe there's a way to fix it on ESP32-C3's side.

Additional context

MOSFET model 1N60C, an additional 1kΩ resistor is used when inverting the SDO. SPI speed is 1MHz.

Edit: wrong resistor value