Pico WH: Issues Display Pack 2.0 / Waveshare Pico-RTC-DS3231

Support
1

Hi there

I have the following issue.

  • Setup:
    Stack with Pico WH / Display Pack 2.0 / Waveshare Pico-RTC-DS3231
    https://shop.pimoroni.com/products/pico-display-pack-2-0
    https://www.waveshare.com/pico-rtc-ds3231.htm

  • Pimoroni build of Micropython:
    pimoroni-picow-v1.22.2-micropython.uf2

  • The RTC module works fine without the Display Pack attached. Time can be set and read.

  • As soon as the Display Pack is attached I either get this error message:

    Traceback (most recent call last):
  File "<stdin>", line 27, in <module>
  File "<stdin>", line 23, in PicoRTCReadTime
OSError: [Errno 110] ETIMEDOUT

  • Or, for whatever reason I managed exactly once to read the time, but it was faulty.

  • I have tried machine.I2C and machine.SoftI2C

  • According to to the schematics both modules use GP20 and GP21, could that be the issue?

I very much appreciate your help!

This is the code for the RTC module:

#!/usr/bin/python
# -*- coding: utf-8 -*-
from machine import I2C, SoftI2C, Pin
import time

address = 0x68
register = 0x00
#sec min hour week day month year
CurrentTime = b'\x00\x42\x21\x01\x19\x05\x24'
week  = ["Sunday","Monday","Tuesday","Wednesday","Thursday","Friday","Saturday"];

# I2C-Pins
i2c_sda = Pin(20)
i2c_scl = Pin(21)

# Initialisation
bus = I2C(0,sda=i2c_sda,scl=i2c_scl,freq=400000)

def PicoRTCSetTime():
	bus.writeto_mem(int(address),int(register),CurrentTime)

def PicoRTCReadTime():
	return bus.readfrom_mem(int(address),int(register),7);

# PicoRTCSetTime() #You can remove this line once time is set
while 1:
	data = PicoRTCReadTime()
	a = data[0]&0x7F  #sec
	b = data[1]&0x7F  #min
	c = data[2]&0x3F  #hour
	d = data[3]&0x07  #week
	e = data[4]&0x3F  #day
	f = data[5]&0x1F  #month
	g = data[6]&0x3F #year
	print("20%x/%02x/%02x %02x:%02x:%02x %s" %(g,f,e,c,b,a,week[d-1])) #year,month,day,hour,min,sec,week
	time.sleep(1)
2

The pin conflict is your issue. The Display sets those pins up for use as SPI, but the RTC also tries to set them up for use as i2c. That’s just not going to work.

1 Like
3

Thanks a lot for the confirmation and taking your time!

It is a pitty for the compact stackable design. I will need to find a way how to rearrange the RTC pins.

Best regards.

1 Like