I2C clock stretching on nrf52840

[MCA]

Hello !

I would like to know if the nrf52840 is affected by the errata https://infocenter.nordicsemi.com/topic/errata_nRF52832_Rev2/ERR/nRF52832/Rev2/latest/anomaly_832_149.html#anomaly_832_149 or something similar ?
(I did not find it in the 52840 errata)

I am struggling to communicate with a 100KHz i2c device which require clock stretching to work. The communication often hang forever.
It sometimes work, the difference seems to be the lenght of the first clock after a stretch.

A non working screenshot :

A working screenshot:


If this is the same issue as the 832 errata, is there a known workarround ?

Thank you for your help.

[MCA]

Hi,

Any plans to update the specs/errata to show that TWI and TWIM share the same issue ?

Anyway, I adapted the bigbang driver from the sdk (deprecated/twi_sw_master.c) to my codebase.
It also had a bug on the 1st clock after a stretch, the fix was trivial though.

	// Pull SCL high and wait a moment for SDA line to settle
	// Make sure slave is not stretching the clock
	transfer_succeeded &= twi_master_wait_while_scl_low(bus);
	TWI_DELAY(); //hack

The clock stretching is now working as expected.
I am making this public in case it can help someone else.

Best regards,
Mathieu

[mahi354]

Hello, sir.

We're having the same problem with our io extender. We're trying to communicate using the bit bagging approach, but it's not working. We checked the clock signals and they're all good, but the slave isn't giving ack bits.

please look once  i sharing the signals

D:\DeviceDownload\nRF5SDK1702d674dde\nRF5_SDK_17.0.2_d674dde\components\drivers_nrf\twi_master\deprecated

I'm using the SDK 17.1.0, and I'm not sure if this driver requires any adjustments to those files to make it work?

can please suggest the what could be the issue with this?