AR1020 Touch Controller Interface

[Brian]

Has anyone used the AR1020 touch controller? If so do you know if it runs at 400Khz or is it limited to 100Khz. I am using the I2C format to clock the data in and out.

The reason I ask is I can talk to it for a read at either speeds(exception of after a write odd code required) but I can't write to it but at 100Khz.

I get a response at 400Khz after a write command of error code $03 which is unrecognized header. It actually takes some usually code just to get the response so I figure it is not recognizing what i am sending. Just stumps me that the read seems to work on pen interrupt trigger but not when sending a command.

I couldn't find where it states this in the data sheet as far as the speed but I did find some examples in SPI mode where it was limited in speed but I wasn't sure how that affected the
I2C speed since it is usually lower than SPI.

[Brian]

The reason I ask is I have multiple things on the I2C buss to limit my main processor pin usage. I have also off loaded the pins needed for the GLCD to an IOExander which is on the I2C buss and everything else runs at 400Khz. I like the speed advantage for the display and the extra processor I/O but I hate to be limited to the 100Khz on my updates to the display just because of the touch controller.

If I am limited I will probably change to the SPI mode and use the extra pins to gain the speed advantage for the display.

thanks in advance for any help.

[Brian]

I got this to work but I had to put it on the MSSP port at 100Khz and separate it from the software controlled I2C control.

I tried putting everything on the MSSP port and switching speeds on the fly to talk to different I2C devices but things went a little hay wire. My comminucation with the AR1020 went crazy when I did this. I probably had something wrong and didn't see it. It was late.