topic MQX4.1.1 I2C example program ran into problem，need help. in MQX Software Solutions

MQX4.1.1 I2C example program ran into problem，need help.

tongjianwu — Tue, 03 Mar 2015 06:41:04 GMT

Hello everyone,

When I use the example program for I2C located in <install_dir>\Freescale\Freescale_MQX_4_1\mqx\examples\i2c,I found the program stop at "result = fwrite (mem, 1, 1, fd);"

The E2PROM type is 24C02.

   mem[0] = (uint8_t)addr;
   printf ("  Write to address 0x%02x ... ", mem[0]);
   do 
   {
      result = fwrite (mem, 1, 1, fd);
      printf("\r\n Hello World \r\n");
   } while (result < 1)

Need help,thks!

Re: MQX4.1.1 I2C example program ran into problem，need help.

poul-erikhansen — Tue, 03 Mar 2015 09:24:46 GMT

I see problems that the driver hangs.
I think it's easiest to modify the polled version.
The drivers in MQX are no specific stable or well written.

Best regards Poul-Erik.

Re: MQX4.1.1 I2C example program ran into problem，need help.

tongjianwu — Tue, 03 Mar 2015 09:35:47 GMT

Thks for your reply,

so what should I do for this problem?

before that, I test the I2C driver for ACCELEROMETER, the program run normally.

after that I test the program for my specific E2PROM,I ran into problems.

Best regard

Re: MQX4.1.1 I2C example program ran into problem，need help.

poul-erikhansen — Tue, 03 Mar 2015 13:11:41 GMT

What we have seen is long time stability problems. We use a 24C128 + some IO port expanders, and it works most of the time. I You can't get it working for the first time, You shod use a logic analyzer or a osciloscop.

Best regards.

Re: MQX4.1.1 I2C example program ran into problem，need help.

tongjianwu — Tue, 03 Mar 2015 13:41:56 GMT

Just now,I test the program for at24c02 and find that " I2C start, send address and get ack ... OK ... ack ==1".

The ACK ought to be '0',now I get ACK=1, I think this is the problem here.

Re: MQX4.1.1 I2C example program ran into problem，need help.

soledad — Tue, 03 Mar 2015 21:01:45 GMT

Hello Tong,

Yes you are right, please check the below thread.

[MQX 4.1]I2C demo for MMA8451Q

Have a great day,
Sol

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Re: MQX4.1.1 I2C example program ran into problem，need help.

tongjianwu — Wed, 04 Mar 2015 03:21:09 GMT

Hello,Poul-Erik.

Can you offer me the E2PROM Demo code?

Thks!

Best Regards!

Re: MQX4.1.1 I2C example program ran into problem，need help.

tongjianwu — Wed, 04 Mar 2015 03:32:18 GMT

Hello,soledad.

I have seen the code for ACCELEROMETER and used for TWR_K70F120M,the program run normally,when I use it for E2PROM,there is NACK for sending slave device address byte.

I use external E2PROM connected to TWR_K70F120M's I2C0 channel for testing,I don't know why this happen.

Thks!

Best Regard!

Re: MQX4.1.1 I2C example program ran into problem，need help.

tongjianwu — Thu, 05 Mar 2015 06:18:12 GMT

Hello every one ,

I have made a mistake,the I2C device address in MQX should be below format:

for example, AT24C02, addr = 1 0 1 0 A2 A1 A0 R/W，this should be shift right one bit (addr>>1),then this parameter pass to MQX I2C driver .

Thks !

Best Regards!