i.MX RT Crossover MCUsのトピックRe: LPI2C doesn't send data

LPI2C doesn't send data

Angel487 — Tue, 05 Sep 2023 14:41:58 GMT

Greetings NXP Community.

I'm trying to establish a connection between an i.MXRT1052 and an external chip via I2C.

For starters I tried to implement both SDK examples, "evkbimxrt1050_lpi2c_interrupt" & "evkbimxrt1050_lpi2c_interrupt_b2b_transfer_master".

Unfortunately when probing with an oscilloscope (in both cases) I see only the SCL line moving (indefinitely), but the SDA line only get pulled low, with no data bits coming out (see attached picture)

Do you have any suggestion to troubleshoot this problem?

Many thanks in advance!

Re: LPI2C doesn't send data

Pavel_Hernandez — Wed, 06 Sep 2023 00:07:49 GMT

Hello, my name is Pavel, and I will be supporting your case, I did the test on my side and this work properly, could you review if your connection is the same as the documentation?

Best regards,
Pavel

Re: LPI2C doesn't send data

Angel487 — Thu, 07 Sep 2023 14:53:49 GMT

Hi Pavel, thanks for the reply.

I'm not using the evaluation board but a custom HW on which the master is LPISC2 and the slave is a sort of memory chip.

Anyway I've found the solution to my problem. In the "pin routing details" MCUexpresso menu, I had to enable the "software Input ON" option to make data coming out of SDA.

Now I'm faced with a new problem, to wakeup the slave device I have to send a special command. The command consists of a
I2C Start event followed by a long period of Logic 0 on the SDA line, then followed a Stop event. I use the two command "LPI2C_MasterStart" and "LPI2C_MasterStop" but the latter does not work (SCL stays low). I hope you can help me with this one.

Thanks in advance

P.S. please see attached files

Re: LPI2C doesn't send data

Pavel_Hernandez — Thu, 07 Sep 2023 23:38:32 GMT

Hello, I suggest reviewing the time of execution of your code and reviewing the seconds in the oscilloscope. I recommend doing this in a bare metal if the NXP library does not work for your application.

I recommend reviewing the information of the slave in some cases the devices as Arduino shields are not at all the time are I2C, for example, I remember I used a capacitive keyboard, but the communication was like an I2C, but it was only 2 wires communication.

Best regards,
Pavel