Regarding SC16IS752IPW not getting configured on I2C Linux driver.

[JK81]

Hello,

We are using attached circuit but we are not able to configure the IC. However, linux driver is able to detect presence of IC on I2C bus. If we try to write value of 0XFF to IODir, we get 0X0F in response. We get similar response for other register like IOstate, IOControl. 

As of now we have disabled all UART related register & just want to focus on GPIO operations, however we don't get any GPIO operation. We did following for troubleshooting.

* Replaced the IC with new one but that didn't helped.

* Verified data on I2C bus & that is OK as per values given, however we don't see the effect from IC.

* When we try to read (after writing 0XFF) to IODir, we always get 0X0F. 

* Changed clock freq. from 100Khz to 50Khz but that didn't had any effect.

I am not sure if the crystal we are using 14.7MHz is causing issues or what as datasheet has mention of 1.8432MHz & 3.072MHz. Kindly help us at earliest.

Regards,

jagdish

[JK81]

We are also using UART apart from GPIO but GPIO are going into some critical modules & hence focusing on GPIO with priority. We have still not checked UART in SC16IS752.

[guoweisun]

This GPIO function is still related with UART interface, I will send to your SC16IS750 Linux driver for reference later.

[JK81]

Hello,

Thanks for providing linux drivers, as of now FW team is trying to implement those & see the results. We will keep you posted of results.

jagdish

[JK81]

Hello NXP support,

Could anyone please respond on above replies.

jagdish

[guoweisun]

1: For the hardware please refer to attached EVB schematic

2: For the software please refer to SPI programming example even if you use the IIC interface but still have reference value.

[JK81]

Hello,

Thanks for providing schematic & reference code. Our schematic looks good based on I2C interface that we are using. Even crystal values are matching, however we are unable to program/ configure GPIOs. The code you provided consist of UART, however we are just accessing GPIOs (GPIO0 - GPIO7) & using below mentioned values of 4 registers.

IOControl=0X00, IOINTEna=0X00, IODir=0XFF (all outputs), IOstate=0XFF.

Do we need anything else to make it working.

jagdish

[guoweisun]

In your system,except GPIO can't be operated,what about others function?