Code für ADS1231

Andreas · April 24, 2017, 8:27pm

thanks a bunch for mentioning the ESP8266 support for the ADS1231 library [1] at the Arduino forum [2], where the original source was taken from. I have had it on my agenda, but there are so many things in flux that this was very much at the bottom of my priority list.

By chance, it seems to have drawn some attention [3], so i have just uploaded some changes [4] to support Atmel SAM (ARM) for Arduino Due.

Cheers,
Andreas.

[1] arduino/libraries/ADS1231 at main · hiveeyes/arduino · GitHub
[2] SPI Load cell chip ADS1231 - #12 by Clemens - Networking, Protocols, and Devices - Arduino Forum
[3] ADS1231 library error build on arduino due · Issue #18 · hiveeyes/arduino · GitHub
[4] arduino/libraries/ADS1231 at ads1231-atmel-sam · hiveeyes/arduino · GitHub

Discussions elsewhere

clemens · April 25, 2017, 12:00am

That’s funny! Many thanks @Andreas!

Cortex M3, ok. I have some Cortex M0 boards here - we had a discussion in the MKR thread - I have today no ADS123x shield for this boards and yet not decided what board could be a good candidate for Open Hive (I think the Autonomo will make it) for a shield. But support for the Cortex M0 could be an issue for the Open Hive / hiveeyes project also in case we will make sound analyzing via I2S and measuring weight with a ADS123x also.

Andreas · June 29, 2017, 12:49pm

Hier einige Alternativen zur ADS1231 Bibliothek von @aerowind, die wir derzeit verwenden, und die ursprünglich aus dem Arduino Forum stammt.

Vielleicht wollen wir diese mal unter die Lupe nehmen? Es gibt Arduino-basierte Bibliotheken/Treiber, und andere.

Arduino

All Arduino libraries are written in C++.

GitHub - ThomasRyanDavies/ADS1231: C++ library for interfacing with ADS1231 24-bit delta-sigma ADC
Barwin cocktail robot
- barwin-arduino/ads1231.h at master · rfjakob/barwin-arduino · GitHub
- barwin-arduino/ads1231.cpp at master · rfjakob/barwin-arduino · GitHub
ADS1231 Breakout
- ADS1231-Breakout/Software/ADS1231 at master · novemberfiveco-engineering/ADS1231-Breakout · GitHub
- via: Breakouts für ADS1231/2/4
Gibt’s nicht mehr
- https://github.com/frecks/ADS1231
- Nur die Index Seite lebt noch im Web Archive weiter: GitHub - frecks/ADS1231: Facilitates communication between an Arduino & an ADS1231.

Non-Arduino

All non-Arduino libraries are written in C, with the exception of the Particle driver, which is also written in C++.

Particle
- GitHub - jensfranke/ads-1231-particle-library
ARM
- ADS1231 - 24-Bit Analog-to-Digital Converter for Bridge Sen… | Mbed
- ARM/Drivers/ADS1231 at master · AqueronteBlog/ARM · GitHub
EUSART-PIC10 / PIC12 / PIC16 / PIC18 MCUs
- GitHub - phaelbotelho/ads1231
nRF52811 SoC
- GitHub - ShpakovDmitry/nRF52811-ADS1231

Andreas · May 26, 2023, 6:21pm

After doing a bit of research on the ADS1231, it appears to me that it also needs to be bit-banged, like the HX711?

At least, this is what I figure when looking at this code.

github.com

ThomasRyanDavies/ADS1231/blob/master/ADS1231.cpp#L65-L70


      
          // Read 24 bits
          for(i=23 ; i >= 0; i--) {
              digitalWrite(pClk, HIGH);
              val = (val << 1) + digitalRead(pData);
              digitalWrite(pClk, LOW);
          }

On this matter, the canonical ADS1231 library by @aerowind, which we are using, may already do that more efficiently by directly manipulating the corresponding registers? Would that even make a difference?

github.com

hiveeyes/arduino/blob/0.17.0/libraries/ADS1231/ADS1231.cpp#L95-L103


      
          	//send pulse to ads1231

              void ADS1231::sclPulse(){

                  volatile PortReg *out;

                  out = portOutputRegister(ADS1231s[this->ADS1231Index].sclPort);

                  *out |= ADS1231s[this->ADS1231Index].sclBit;    // set sclPin high

          //		delayMicroseconds(1);

                  out = portOutputRegister(ADS1231s[this->ADS1231Index].sclPort);

                  *out &= ~ADS1231s[this->ADS1231Index].sclBit;   // set sclPin low

          	}

github.com

hiveeyes/arduino/blob/0.17.0/libraries/ADS1231/ADS1231.cpp#L71-L85


      
              //read data from ads1231

              long ADS1231::readData(){

          		long dataValue = 0;

                  uint8_t inputStatus;

          		for( uint8_t count = 0 ; count < 25 ; count++ ){

          			// send pulse to SCL and read the data

          			sclPulse();

                      if( *portInputRegister(ADS1231s[this->ADS1231Index].dataPort) & (ADS1231s[this->ADS1231Index].dataBit) ) {

                          inputStatus = HIGH; }

                      else {

                          inputStatus = LOW; }

          			dataValue |= (long)(inputStatus) << (31 - count);

          		}

          		return dataValue;

              }

Ah, I see. All the ADS123X needs to be bit-banged.

github.com

hardmax/ADS1232/blob/main/src/ADS1232.cpp#L153-L164


      
          // Read 24 bits
          for(i=23 ; i >= 0; i--) {
              digitalWrite(_pin_SCLK, HIGH);
              #if FAST_CPU
              delayMicroseconds(1);
              #endif
              value = (value << 1) + digitalRead(_pin_DOUT);
              digitalWrite(_pin_SCLK, LOW);
              #if FAST_CPU
              delayMicroseconds(1);
              #endif
          }

… and others are even using the same detection macros we added to the HX711 driver the other day. Funny.

github.com

hardmax/ADS1232/blob/main/src/ADS1232.cpp#L16-L26


      
          // Whether we are running on either the ESP8266 or the ESP32.
          #define ARCH_ESPRESSIF (defined(ARDUINO_ARCH_ESP8266) || defined(ARDUINO_ARCH_ESP32))
          
          
// Define macro designating whether we're running on a reasonable
          // fast CPU and so should slow down sampling from GPIO.
          #define FAST_CPU \
              ( \
              ARCH_ESPRESSIF || \
              defined(ARDUINO_ARCH_SAM)     || defined(ARDUINO_ARCH_SAMD) || \
              defined(ARDUINO_ARCH_STM32)   || defined(TEENSYDUINO) \
              )

Apologies that I got the wrong impression on this detail. It is only the NAU7802, which has a more advanced interface that does not require bit-banging – I²C in this case?

Andreas · May 26, 2023, 6:26pm

At least, it may have unfortunate consequences on compatibility aspects with other MCUs.

This is why I am thinking about using ThomasRyanDavies/ADS1231 on hiveeyes/arduino instead. However, I haven’t evaluated if that would be feasible, or if some functionality would be missing.

Andreas · May 26, 2023, 6:37pm

Maybe it is not a good idea, as we apparently added a few production-like adjustments around interrupt masking, or such, to the @aerowind driver we are maintaining. However, the other fix needed to mitigate the type conversion error indeed is about that this routine directly uses CPU registers, instead of Arduino HAL functions, and could have been avoided if the driver would use those instead.

– https://github.com/hiveeyes/arduino/blob/main/libraries/ADS1231/CHANGES.rst

So, we will probably not change too much in this area. However, as I see the chips are really that similar from a software interfacing perspective, and that others are also using the CPU fastness detection macros we introduced to the HX711 driver, I am wondering if “baking a good ADS123X driver” could eventually mean to “just wrap the HX711 driver”, and add a single dedicated power-up/down-by-gpio routine on top, which may be the only effective difference then?

Apologies that I may be a bit late with my understanding of the underpinnings. I’ve actually not looked at ADS123X drivers that much until just now.

Andreas · May 28, 2023, 11:00am

Improvements

The ADS1231 library by @aerowind, picked up from the Arduino Forum the other day ^[1], has now been separated into a dedicated repository.

Interrupt masking has been implemented by the library already, we only made it compile on ESP8266 by removing the register manipulation code at this place, and using the corresponding Arduino HAL routines instead, see error: 'SREG' was not declared in this scope · Issue #1 · hiveeyes/aerowind-ads1231 · GitHub.

Indeed, it will not be compatible with ESP32 for this reason. I’ve added a recommendation to the README to use GitHub - ThomasRyanDavies/ADS1231: C++ library for interfacing with ADS1231 24-bit delta-sigma ADC instead.

Flaws ahead

However, the ThomasRyanDavies/ADS1231 library may need to be improved with respect to interrupt masking. Also, both libraries will probably suffer from CPU fastness woes, similar to the HX711 library before Spring cleaning with multiarch support by amotl · Pull Request #123 · bogde/HX711 · GitHub. Only the other driver for the ADS1232, hardmax/ADS1232, has appropriate compensation code.

SPI Load cell chip ADS1231 - #6 by system - Networking, Protocols, and Devices - Arduino Forum ↩︎