Is there a possibility to send single Bytes with Cy7C65215 and ignore NACK?

[MMu_3620651]

Hey there,

we want to implement a "start sequence" with CY7C65215 via i2c. The following seqence needs to be realized:

Start - 0x04 - NotACK --- RepeatedStart - 0x34 - NotACK --- RepeatedStart - 0x06 - NotACK --- RepeatedStart - 0x36 - NotACK - Stop

Of course this is kind of strange because none of the four messages will be acknowledged. And it does not really comply with i2c. Basically, we need to set isStopBit argument to 0, call CyI2cWrite() three times with the desired byte as slave address and ignore NotACK each time. Then call CyI2cWrite() one last time with isStopBit set to 1.

This would realize the sequence but unfortunately there are some restrictions like minimum data buffer length.

Any ideas?

Regards,

Marco

[YatheeshD_36]

Hello Marco,

Please refer to Cypress USB-Serial API documentation CY_I2C_DATA_CONFIG where you can disable the stop bit and reconfigure using  CySetI2cConfig whenever a stop bit is needed .

Also refer to the I2C master example codes in the USB-Serial SDK.

Best Regards,

Yatheesh

[MMu_3620651]

Hi Yatheesh,

thanks for your fast response. The ordinary i2c communication using USB-serial API does work very well, no problems with that. But an application-specific chip does require the sequence described in my first post. Please see also the picture attached, I think it's clear then. This sequence requires: a) to ignore NotAcknowledge and b) sending only one byte or induce a repeated start.

After some research and reading a lot of source code, I think it's not possible with CY7C65215 and we have to find an other solution.

Regards,

Marco

[YatheeshD_36 · Accepted solution]

Hello,

The default firmware provided with CY7C65215 cannot ignore ACKs or NAKs from the slave and we do not provide an option to change it.

Best Regards,

Yatheesh