[Feature Request]: sensors i2c (bme280, ahtxx,...) in XIAO nRF52840 y Wio-SX1262

[Javito68]

Platform

NRF52

Description

Hello, I have the XIAO nRF52840 and Wio-SX1262 kits. Which pins do I need to use to get a BME 280 I2C sensor working? I have firmware version 2.7.15 beta installed and I've tried pins D4, D5, D6, and D7, but it's not working. Any ideas? Thanks and regards.

[porkcube]

Seeed decided to use D6/D7 as UART for GPS in their official firmware, however there is a seeed_xiao_nrf52840_kit_i2c variant that instead uses D6 (SDA) and D7 (SCL) for i2c if you're willing to try compiling yourself.

firmware/variants/nrf52840/seeed_xiao_nrf52840_kit/variant.h

Lines 188 to 189 in 68250dc

	#define PIN_WIRE_SDA D6
	#define PIN_WIRE_SCL D7

[tilllt]

@porkcube Would it be possible to include the i2c variant in the web flasher? With time and effort I might be able to build this myself but it would be so much easier if it was part of the regular build workflow of Meshtastic.

In my attempts to compile the i2c variant, i encountered these problems:

c:/users/user/.platformio/packages/toolchain-gccarmnoneeabi/bin/../lib/gcc/arm-none-eabi/9.3.1/../../../../arm-none-eabi/bin/ld.exe: .pio/build/seeed_xiao_nrf52840_kit_i2c/firmware-seeed_xiao_nrf52840_kit_i2c-2.7.18.7d4600f.elf section `.text' will not fit in region `FLASH'
c:/users/user/.platformio/packages/toolchain-gccarmnoneeabi/bin/../lib/gcc/arm-none-eabi/9.3.1/../../../../arm-none-eabi/bin/ld.exe: region `FLASH' overflowed by 120712 bytes

[spfmoby]

Same error here with the 2.7.17
It worked like a charm with the 2.7.15

[porkcube]

@porkcube Would it be possible to include the i2c variant in the web flasher? With time and effort I might be able to build this myself but it would be so much easier if it was part of the regular build workflow of Meshtastic.

In my attempts to compile the i2c variant, i encountered these problems:

c:/users/user/.platformio/packages/toolchain-gccarmnoneeabi/bin/../lib/gcc/arm-none-eabi/9.3.1/../../../../arm-none-eabi/bin/ld.exe: .pio/build/seeed_xiao_nrf52840_kit_i2c/firmware-seeed_xiao_nrf52840_kit_i2c-2.7.18.7d4600f.elf section `.text' will not fit in region `FLASH'
c:/users/user/.platformio/packages/toolchain-gccarmnoneeabi/bin/../lib/gcc/arm-none-eabi/9.3.1/../../../../arm-none-eabi/bin/ld.exe: region `FLASH' overflowed by 120712 bytes

The official firmware version in the official flasher is Seeed's own, they decided to opt for GPS support on those pins instead of i2c so an "official" variant is very unlikely.

I have hit the FLASH overflowed compiling locally myself, the trick seems to be not just reassigning D6/7 to i2c but removing all GPS references in variant.h/platform.io to slim it back down.

[tilllt]

Sorry, could you be more specific what we have to edit out? I can't seem the find exactly what needs to commented out to make compilation work.

[spfmoby]

Here is what I've done:

variant.cpp:

#include "variant.h"
#include "configuration.h"
#include "nrf.h"
#include "wiring_constants.h"
#include "wiring_digital.h"
#include <map>
#include <memory>
#include <stddef.h>
#include <stdint.h>
const uint32_t g_ADigitalPinMap[] = {
    // D0 .. D13
    2,  // D0  is P0.02 (A0)
    3,  // D1  is P0.03 (A1)
    28, // D2  is P0.28 (A2)
    29, // D3  is P0.29 (A3)
    4,  // D4  is P0.04 (A4,SDA)
    5,  // D5  is P0.05 (A5,SCL)
    43, // D6  is P1.11 (TX)
    44, // D7  is P1.12 (RX)
    45, // D8  is P1.13 (SCK)
    46, // D9  is P1.14 (MISO)
    47, // D10 is P1.15 (MOSI)

    // LEDs
    26, // D11 is P0.26 (LED RED)
    6,  // D12 is P0.06 (LED BLUE)
    30, // D13 is P0.30 (LED GREEN)
    14, // D14 is P0.14 (READ_BAT)

    // LSM6DS3TR
    40, // D15 is P1.08 (6D_PWR)
    27, // D16 is P0.27 (6D_I2C_SCL)
    7,  // D17 is P0.07 (6D_I2C_SDA)
    11, // D18 is P0.11 (6D_INT1)

    // MIC
    42, // D19 is P1.10 (MIC_PWR)
    32, // D20 is P1.00 (PDM_CLK)
    16, // D21 is P0.16 (PDM_DATA)

    // BQ25100
    13, // D22 is P0.13 (HICHG)
    17, // D23 is P0.17 (~CHG)

    //
    21, // D24 is P0.21 (QSPI_SCK)
    25, // D25 is P0.25 (QSPI_CSN)
    20, // D26 is P0.20 (QSPI_SIO_0 DI)
    24, // D27 is P0.24 (QSPI_SIO_1 DO)
    22, // D28 is P0.22 (QSPI_SIO_2 WP)
    23, // D29 is P0.23 (QSPI_SIO_3 HOLD)

    // NFC
    9,  // D30 is P0.09 (NFC1)
    10, // D31 is P0.10 (NFC2)

    // VBAT
    31, // D32 is P0.10 (VBAT)
};

/*
  Copyright (c) 2014-2015 Arduino LLC.  All right reserved.
  Copyright (c) 2016 Sandeep Mistry All right reserved.
  Copyright (c) 2018, Adafruit Industries (adafruit.com)

  This library is free software; you can redistribute it and/or
  modify it under the terms of the GNU Lesser General Public
  License as published by the Free Software Foundation; either
  version 2.1 of the License, or (at your option) any later version.

  This library is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
  See the GNU Lesser General Public License for more details.

  You should have received a copy of the GNU Lesser General Public
  License along with this library; if not, write to the Free Software
  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
*/

void initVariant()
{
    // Set BQ25101 ISET to 100mA instead of 50mA
    pinMode(HICHG, OUTPUT);
    digitalWrite(HICHG, LOW);

    // LEDs
    pinMode(PIN_LED1, OUTPUT);
    ledOff(PIN_LED1);

    pinMode(PIN_LED2, OUTPUT);
    ledOff(PIN_LED2);

    pinMode(PIN_LED3, OUTPUT);
    ledOff(PIN_LED3);
}

And variant.h:

#ifndef _SEEED_XIAO_NRF52840_KIT_H_
#define _SEEED_XIAO_NRF52840_KIT_H_

/** Master clock frequency */
#define VARIANT_MCK (64000000ul)

#define USE_LFXO // Board uses 32khz crystal for LF
// #define USE_LFRC    // Board uses RC for LF

/*----------------------------------------------------------------------------
 *        Headers
 *----------------------------------------------------------------------------*/

#include "WVariant.h"

#ifdef __cplusplus
extern "C" {
#endif // __cplusplus

#define PINS_COUNT (33)
#define NUM_DIGITAL_PINS (33)
#define NUM_ANALOG_INPUTS (8)
#define NUM_ANALOG_OUTPUTS (0)

/*
 * Digital Pins
 */
#define D0 (0ul)
#define D1 (1ul)
#define D2 (2ul)
#define D3 (3ul)
#define D4 (4ul)
#define D5 (5ul)
#define D6 (6ul)
#define D7 (7ul)
#define D8 (8ul)
#define D9 (9ul)
#define D10 (10ul)

/*
 * Analog pins
 */
#define PIN_A0 (0)
#define PIN_A1 (1)
#define PIN_A2 (32)
#define PIN_A3 (3)
#define PIN_A4 (4)
#define PIN_A5 (5)
#define PIN_VBAT (32)
#define VBAT_ENABLE (14)

static const uint8_t A0 = PIN_A0;
static const uint8_t A1 = PIN_A1;
static const uint8_t A2 = PIN_A2;
static const uint8_t A3 = PIN_A3;
static const uint8_t A4 = PIN_A4;
static const uint8_t A5 = PIN_A5;
#define ADC_RESOLUTION 12

/*
 * LEDs
 */
#define LED_STATE_ON (0) // RGB LED is common anode
#define LED_RED (11)
#define LED_GREEN (13)
#define LED_BLUE (12)

#define PIN_LED1 LED_GREEN // PIN_LED1 is used in src/platform/nrf52/architecture.h to define LED_PIN
#define PIN_LED2 LED_BLUE
#define PIN_LED3 LED_RED

#define LED_BUILTIN LED_RED // LED_BUILTIN is used by framework-arduinoadafruitnrf52 to indicate flash writes

#define LED_PWR LED_RED
#define USER_LED LED_BLUE

/*
 * Buttons
 */

/*
 * D0 is shared with PIN_GPS_STANDBY on the L76K GNSS Module, so refer to
 * GPS_L76K definition preventing this conflict
 */

// #define BUTTON_PIN D0

/*
 * Serial Interfaces
 */
#define PIN_SERIAL2_RX (-1)
#define PIN_SERIAL2_TX (-1)

/*
 * Pinout for SX126x
 */
#define USE_SX1262

#ifdef XIAO_BLE_LEGACY_PINOUT
// Legacy xiao_ble variant pinout for third-party SX126x modules e.g. EBYTE E22
#define SX126X_CS D0
#define SX126X_DIO1 D1
#define SX126X_BUSY D2
#define SX126X_RESET D3
#define SX126X_RXEN D7

#elif defined(SEEED_XIAO_WIO_BTB)
// Wio-SX1262 for XIAO with 30-pin board-to-board connector
// https://files.seeedstudio.com/products/SenseCAP/Wio_SX1262/Schematic_Diagram_Wio-SX1262_for_XIAO.pdf
#define SX126X_CS D3
#define SX126X_DIO1 D0
#define SX126X_BUSY D1
#define SX126X_RESET D2
#define SX126X_RXEN D4
#else
// Wio-SX1262 for XIAO (standalone SKU 113010003 or nRF52840 kit SKU 102010710)
// https://files.seeedstudio.com/products/SenseCAP/Wio_SX1262/Wio-SX1262%20for%20XIAO%20V1.0_SCH.pdf
#define SX126X_CS D4
#define SX126X_DIO1 D1
#define SX126X_BUSY D3
#define SX126X_RESET D2
#define SX126X_RXEN D5
#endif

// Common pinouts for all SX126x pinouts above
#define SX126X_TXEN RADIOLIB_NC
#define SX126X_DIO2_AS_RF_SWITCH // DIO2 is used to control the TX side of the RF switch
#define SX126X_DIO3_TCXO_VOLTAGE 1.8

/*
 * SPI Interfaces
 * Defined after pinout for SX1262x to factor in CS pinout variations
 */
#define SPI_INTERFACES_COUNT 1

#define PIN_SPI_MISO D9
#define PIN_SPI_MOSI D10
#define PIN_SPI_SCK D8

static const uint8_t SS = SX126X_CS;
static const uint8_t MOSI = PIN_SPI_MOSI;
static const uint8_t MISO = PIN_SPI_MISO;
static const uint8_t SCK = PIN_SPI_SCK;

/*
 * GPS
 */
// GPS L76K
#define PIN_SERIAL1_RX (-1)
#define PIN_SERIAL1_TX (-1)

/*
 * Battery
 */
#define BATTERY_PIN PIN_VBAT      // P0.31: VBAT voltage divider
#define ADC_MULTIPLIER (3)        // ... R17=1M, R18=510k
#define ADC_CTRL VBAT_ENABLE      // P0.14: VBAT voltage divider
#define ADC_CTRL_ENABLED LOW      // ... sink
#define EXT_CHRG_DETECT (23)      // P0.17: Charge LED
#define EXT_CHRG_DETECT_VALUE LOW // ... BQ25101 ~CHG indicates charging
#define HICHG (22)                // P0.13: BQ25101 ISET 100mA instead of 50mA

#define BATTERY_SENSE_RESOLUTION_BITS (10)

/*
 * Wire Interfaces
 * Keep this section after potentially conflicting pin definitions
 */
#define I2C_NO_RESCAN // I2C is a bit finicky, don't scan too much
#define WIRE_INTERFACES_COUNT 1


#define PIN_WIRE_SDA D6
#define PIN_WIRE_SCL D7


static const uint8_t SDA = PIN_WIRE_SDA;
static const uint8_t SCL = PIN_WIRE_SCL;

/*
 * Buttons
 * Keep this section after potentially conflicting pin definitions
 * because D0 has multiple possible conflicts with various XIAO modules:
 * - PIN_GPS_STANDBY on the L76K GNSS Module
 * - DIO1 on the Wio-SX1262 - 30-pin board-to-board connector version
 * - SX1262X CS on XIAO BLE legacy pinout
 */

#if !defined(GPS_L76K) && !defined(SEEED_XIAO_WIO_BTB) && !defined(XIAO_BLE_LEGACY_PINOUT)
#define BUTTON_PIN D0
#endif

#ifdef __cplusplus
}
#endif

/*----------------------------------------------------------------------------
 *        Arduino objects - C++ only
 *----------------------------------------------------------------------------*/

#endif

```It now compiles without error but ATM I don't have a Xiao with a temperature sensor to test.

[tilllt]

@spfmoby i think i am doing something entirely wrong, even with your files i am running into the memory error.
@porkcube generally speaking, can the memory issue be adressed with compiler optimiziation flags in platform.ini or do there need to be actual code changes?

[porkcube]

Hrmm try adding build_unflags = -DGPS_L76K below the build_flags in your platformio.ini which should disable all the GPS stuff (sorry working on custom nrf52840 variant at the moment but it is compiling cleaning on 2.7.18/.19 without anything GPS)

[madeofstown]

@porkcube env:seeed_xiao_nrf52840_kit_i2c uses the build_unflags = -DGPS_L76K and still fails to build with the final error:

/home/user/.platformio/packages/toolchain-gccarmnoneeabi/bin/../lib/gcc/arm-none-eabi/9.3.1/../../../../arm-none-eabi/bin/ld: .pio/build/seeed_xiao_nrf52840_kit_i2c/firmware-seeed_xiao_nrf52840_kit_i2c-2.7.19.7fbe5e1.elf section `.text' will not fit in region `FLASH'
/home/user/.platformio/packages/toolchain-gccarmnoneeabi/bin/../lib/gcc/arm-none-eabi/9.3.1/../../../../arm-none-eabi/bin/ld: region `FLASH' overflowed by 124392 bytes
collect2: error: ld returned 1 exit status
*** [.pio/build/seeed_xiao_nrf52840_kit_i2c/firmware-seeed_xiao_nrf52840_kit_i2c-2.7.19.7fbe5e1.elf] Error 1
======================================================================================= [FAILED] Took 32.63 seconds =======================================================================================

Environment                  Status    Duration
---------------------------  --------  ------------
seeed_xiao_nrf52840_kit_i2c  FAILED    00:00:32.625
================================================================================== 1 failed, 0 succeeded in 00:00:32.625 ==================================================================================

[tilllt]

I saw that you converted the issue to a "feature request" and thus a discussion.

I don't think it's a feature request, but rather a bug because there is a designated firmware to use with the Seeed Xiao nRF52 which doesn't work.

1. In recent versions, it didn't compile for space issues, neither on the development nor the master branch.

2. In any case, It never worked with i2c sensors, without tweaks. We had to manually change stuff in the firmware to have sensor support, even in the i2c variant.

Could you elaborate why this is considered a feature request, I had assumed working i2c and sensor support is one of the core functionality of Meshtastic?

[porkcube]

Purely conjecture on my part.... but as has already been mentioned Seeed decided to use D6/D7 as UART for GPS in their officially supported variant which would make i2c non-viable due to the limited # of pins, thus this is for "unofficial" DIY variants.

[tilllt]

There are other connectors on the Seeed Xiao that have no purpose in the context of Meshtastic like the NFC pads.

In any case, I think:

1. It's possible to make i2c sensors usable with the Seeed Xiao nrF52 (even with GPS)
2. Using i2c sensors is a core functionality of Meshtastic

So these two points make this more seem like a bug than a feature request.

[porkcube]

I think you're not understanding the difference between official firmware (as in a company, in this case Seeed, has sponsored Meshtastic financially and committed to supporting hw in a certain configuration for some duration of time) and diy variants (where it's user/community contributed and more open to reassigning pins for alternate functionality).
See #8866 as example of work to reign in/unify all the Xiao nRF52840 variants where it's more appropriate to remap pin(s) for desired functionality the official firmware lacks.

[tilllt]

Ok, so if we look into the platform.ini of the Seeed Xiao nRF52, there are two variants of the device defined.

seeed_xiao_nrf52840_kit
seeed_xiao_nrf52840_kit_i2c

Neither works with i2c sensors.

I think they both refer to the "original" manufacturers firmware, with the i2c variant trying to solve the GPS / i2c pins problem, but fails.

To get back to the starting point of the discussion: I would call that a bug.

In earlier versions of Meshtastic, this i2c version seem to have worked, now it doesn't.