Raspberry Pi Pico I2C pins not working (MicroPython) - i2c

Question

I have connected an ssd1306 OLED and BME280 to my Pico. Everything works like a charm when connected to Pin 0 (sda) and 1 (scl) i2c pins. But due to my very bad planning, I have to switch to any other i2c pins. Once connected I cannot get it to work.
I have changed from i2c = machine.I2C(0, scl=machine.Pin(1), sda=machine.Pin(0),freq=400000) to i2c = machine.I2C(0, scl=machine.Pin(13), sda=machine.Pin(12),freq=400000) and others, but to no avail.
Code snippet:
import machine
import bme280
import time
from machine import Pin, I2C, ADC
from ssd1306 import SSD1306_I2C
i2c = machine.I2C(0, scl=machine.Pin(13), sda=machine.Pin(12),freq=400000)
bme = bme280.BME280(i2c=i2c)
oled = SSD1306_I2C(128, 64, i2c)
Error I'm getting is:
Traceback (most recent call last): File "<stdin>", line 9, in <module> File "/lib/bme280.py", line 75, in __init__ OSError: 5
Which is:
dig_88_a1 = self.i2c.readfrom_mem(self.address, 0x88, 26) from bme280.py (standard driver)
I have performed an i2c scan and it does return correct addresses on the new pins.

Answer 1

So I had a Similar Problem to you I had the ssd1306 OLED and I kept getting
\\Traceback (most recent call last):
File "<stdin>", line 5, in <module>
File "/lib/ssd1306.py", line 110, in __init__
File "/lib/ssd1306.py", line 36, in __init__
File "/lib/ssd1306.py", line 71, in init_display
File "/lib/ssd1306.py", line 115, in write_cmd
OSError: [Errno 5] EIO
Im running the QT PI from addafuit but its a RP2040 chip and I'm running micro python.
Anyhow, I pressed the restart button on the board and It magically started working. Just like you, my i2c scan was getting the right address.
the code I ended up using that worked for me was
from machine import Pin, I2C
from ssd1306 import SSD1306_I2C
i2c = I2C(0,sda=Pin(24),scl=Pin(25),freq=40000)
oled = SSD1306_I2C(128,64,i2c)
oled.fill(0)
oled.text("Hello",0,0)
oled.show()
and for the ssd1306 driver, I used
# MicroPython SSD1306 OLED driver, I2C and SPI interfaces
from micropython import const
import framebuf
# register definitions
SET_CONTRAST = const(0x81)
SET_ENTIRE_ON = const(0xA4)
SET_NORM_INV = const(0xA6)
SET_DISP = const(0xAE)
SET_MEM_ADDR = const(0x20)
SET_COL_ADDR = const(0x21)
SET_PAGE_ADDR = const(0x22)
SET_DISP_START_LINE = const(0x40)
SET_SEG_REMAP = const(0xA0)
SET_MUX_RATIO = const(0xA8)
SET_COM_OUT_DIR = const(0xC0)
SET_DISP_OFFSET = const(0xD3)
SET_COM_PIN_CFG = const(0xDA)
SET_DISP_CLK_DIV = const(0xD5)
SET_PRECHARGE = const(0xD9)
SET_VCOM_DESEL = const(0xDB)
SET_CHARGE_PUMP = const(0x8D)
# Subclassing FrameBuffer provides support for graphics primitives
# http://docs.micropython.org/en/latest/pyboard/library/framebuf.html
class SSD1306(framebuf.FrameBuffer):
def __init__(self, width, height, external_vcc):
self.width = width
self.height = height
self.external_vcc = external_vcc
self.pages = self.height // 8
self.buffer = bytearray(self.pages * self.width)
super().__init__(self.buffer, self.width, self.height, framebuf.MONO_VLSB)
self.init_display()
def init_display(self):
for cmd in (
SET_DISP | 0x00, # off
# address setting
SET_MEM_ADDR,
0x00, # horizontal
# resolution and layout
SET_DISP_START_LINE | 0x00,
SET_SEG_REMAP | 0x01, # column addr 127 mapped to SEG0
SET_MUX_RATIO,
self.height - 1,
SET_COM_OUT_DIR | 0x08, # scan from COM[N] to COM0
SET_DISP_OFFSET,
0x00,
SET_COM_PIN_CFG,
0x02 if self.width > 2 * self.height else 0x12,
# timing and driving scheme
SET_DISP_CLK_DIV,
0x80,
SET_PRECHARGE,
0x22 if self.external_vcc else 0xF1,
SET_VCOM_DESEL,
0x30, # 0.83*Vcc
# display
SET_CONTRAST,
0xFF, # maximum
SET_ENTIRE_ON, # output follows RAM contents
SET_NORM_INV, # not inverted
# charge pump
SET_CHARGE_PUMP,
0x10 if self.external_vcc else 0x14,
SET_DISP | 0x01,
): # on
self.write_cmd(cmd)
self.fill(0)
self.show()
def poweroff(self):
self.write_cmd(SET_DISP | 0x00)
def poweron(self):
self.write_cmd(SET_DISP | 0x01)
def contrast(self, contrast):
self.write_cmd(SET_CONTRAST)
self.write_cmd(contrast)
def invert(self, invert):
self.write_cmd(SET_NORM_INV | (invert & 1))
def show(self):
x0 = 0
x1 = self.width - 1
if self.width == 64:
# displays with width of 64 pixels are shifted by 32
x0 += 32
x1 += 32
self.write_cmd(SET_COL_ADDR)
self.write_cmd(x0)
self.write_cmd(x1)
self.write_cmd(SET_PAGE_ADDR)
self.write_cmd(0)
self.write_cmd(self.pages - 1)
self.write_data(self.buffer)
class SSD1306_I2C(SSD1306):
def __init__(self, width, height, i2c, addr=0x3C, external_vcc=False):
self.i2c = i2c
self.addr = addr
self.temp = bytearray(2)
self.write_list = [b"\x40", None] # Co=0, D/C#=1
super().__init__(width, height, external_vcc)
def write_cmd(self, cmd):
self.temp[0] = 0x80 # Co=1, D/C#=0
self.temp[1] = cmd
self.i2c.writeto(self.addr, self.temp)
def write_data(self, buf):
self.write_list[1] = buf
self.i2c.writevto(self.addr, self.write_list)
class SSD1306_SPI(SSD1306):
def __init__(self, width, height, spi, dc, res, cs, external_vcc=False):
self.rate = 10 * 1024 * 1024
dc.init(dc.OUT, value=0)
res.init(res.OUT, value=0)
cs.init(cs.OUT, value=1)
self.spi = spi
self.dc = dc
self.res = res
self.cs = cs
import time
self.res(1)
time.sleep_ms(1)
self.res(0)
time.sleep_ms(10)
self.res(1)
super().__init__(width, height, external_vcc)
def write_cmd(self, cmd):
self.spi.init(baudrate=self.rate, polarity=0, phase=0)
self.cs(1)
self.dc(0)
self.cs(0)
self.spi.write(bytearray([cmd]))
self.cs(1)
def write_data(self, buf):
self.spi.init(baudrate=self.rate, polarity=0, phase=0)
self.cs(1)
self.dc(1)
self.cs(0)
self.spi.write(buf)
self.cs(1)
So the only advice and can give to you is to try to press the restart button.