Use i2c pins with interrupt

[Anonymous]

Hi all,

I want to use SL3S4011 tag with i2c interrupt. It pull low to scl signal for a 200uS(Attached) when tag is readed from rf. I read the datasheet but I couldn't find a solution how I can detect isr signal.

I tried to show i2c pins and connect them an isr but i2c master mode don't support this mode.

Do you have any solution ?

Thank you

[RyanZhao]

Hi Burak,

200us is 5KHz clock. I2C slave(SL3S4011) pulls SCL low for 200us. It sound like "clock stretching". The good news is that PSoC4 supports clock stretching.

But I have no idea about how to capture stretching event in PSoC4, maybe using a Timer to count LOW time of SCL, maybe just a status register can make it without customized code.

Let's double-check I2C master code details....

Thanks,

Ryan

[Anonymous]

Hi again,

Actually my problem is not detect this signal, I want to wake up with this signal from sleep modes. Normally if this connect to 2 pins, I could connect pin to isr in top desing and I could wake and I could understand the SL3S4011 is written from rf. But now I couldn't detect this signal with isr.

I need to connect i2c sda pin to isr. But in datasheets and forum, I didn't find any solution about this needed.

[RodolfoGL · Accepted solution]

You can use a third pin and connect it to the SDA line externally.

When using the I2C block, the pins consumed by the block are dedicated for the digital interface, so you can't connect them to other parts of the system, like an ISR.

[Anonymous]

Ok. Thanks for your help.

Regards.