topic Re: IMXRT105x LPI2C STOP generated when using kLPI2C_TransferNoStopFlag in i.MX RT Crossover MCUs

IMXRT105x LPI2C STOP generated when using kLPI2C_TransferNoStopFlag

gavin5342 — Wed, 09 Aug 2023 13:35:41 GMT

I want to generate a write (for a command) without STOP followed by a read with a repeated START.

When I use LPI2C_RTOS_Transfer to send a transfer with kLPI2C_TransferNoStopFlag set, I see the STOP condition is generated on the I2C bus as though kLPI2C_TransferDefaultFlag were set.

Has anyone else seen this and/or know how to fix?

A workaround would be to make the command subaddress, but I would need to ignore the NAK that the slave sends when it has received the command.

Re: IMXRT105x LPI2C STOP generated when using kLPI2C_TransferNoStopFlag

gavin5342 — Thu, 10 Aug 2023 09:36:02 GMT

There seems to be a timeout that I am missing as the transactons work as I expect if I don't insert a breakpoint in between.

Re: IMXRT105x LPI2C STOP generated when using kLPI2C_TransferNoStopFlag

EdwinHz — Thu, 10 Aug 2023 17:48:37 GMT

Hi @gavin5342,

I2C timings often will be affected by debug halts, which is why the LPI2C module features a debug mode, described on Section "46.3.4 Debug mode" of the Reference Manual. You could try implementing this feature for further debugging.

BR,
Edwin.