Notifications
Clear all
Topic starter
12/09/2025 3:35 pm
I don't see the I2c Adresses 0x68/0x69, I only see 6a..6f as in the attached Image.
I have an other I2C Device on Adress 0x38 which works without any issue, so i think the bus should be ok.
I cant find anything about pull-up resistors on the UPS Pico, i habe some on my other Device 0x38.
Any suggestions?
Topic starter
12/09/2025 3:36 pm
After some time then from time to time the 0x68 / 0x69 are shown with i2cdetect, but even then Pico_status has an IO-Error (attached image)...
12/09/2025 11:25 pm
I don't see the I2c Adresses 0x68/0x69, I only see 6a..6f as in the attached Image.
I have an other I2C Device on Adress 0x38 which works without any issue, so i think the bus should be ok.
I cant find anything about pull-up resistors on the UPS Pico, i habe some on my other Device 0x38.
Any suggestions?
Hi,
You need to decrease the speed of the I2C to lower rate, i.e. 25K. Please advise
The I2C pull-up resistors are on the Raspberry Pi PCB and not to be on the UPS PIco I2C also.
Please keep me informed
Best Regards
PiM
12/09/2025 11:32 pm
After some time then from time to time the 0x68 / 0x69 are shown with i2cdetect, but even then Pico_status has an IO-Error (attached image)...
Hi,
Please decrease the speed of the I2C on the Raspberry Pi.
--------------------------
Decreasing the Raspberry Pi I2C rate
The Raspberry Pi I2C driver has a bug, well known – as a stretching problem. This because that Raspberries Pi are not waiting for the peripheral if it is not fast enough. It was not so important for the former interaction way, as the access to the I2C, was only if user requests data from the UPS Pico. The UPS Pico is requiring the stretching in most of the cases, as it is slower that Raspberry Pi. The new driver is using the I2C as an interaction way with UPS Pico, therefore the possibility of missed access is important. To overcome this problem user, need to slow down the rate of the Raspberry Pi to lower one from the 100K as it is by default. We propose to slowdown to 50K or even less i.e. to 25. This will not affect any other peripheral using the I2C interface. This can be done by editing the config.txt and adding the following lines
sudo nano /boot/config.txt
[PICO]
# Added for PIco
enable_uart=1
dtoverlay=i2c-rtc,ds1307
dtparam=i2c_arm=on
dtparam=i2c1_baudrate=5000
------------------------
Please check the manual PAGE 50
Best Regards PiM
