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LPC1830 GPIO for SW I2C configuration

Question asked by Ken Su on Jul 20, 2017
Latest reply on Aug 1, 2017 by soledad

Hi,

 

I use LPC1830 GPIO for SW i2c use,

 

My GPIO pin configuration for SDA and SCL is -->

"SCU_MODE_INBUFF_EN | SCU_MODE_ZIF_DIS | SCU_MODE_FUNC0"

 

My HW Schematic has pull high resistors,

 

1. Should I use "SCU_MODE_INACT" for my SDA, SCL pin configuration if I has pull high resistors?

 

2. To simulate I2C, my SDA GPIO need to set output, it need also to read input to check ACK, when I set to output mode and if I want to read input, should I set to input mode before I read? As I know, it can read input level even in output mode.

 

3. If I connect a i2c slave device and change SDA pin to input mode from output mode, there is an small purse when mode change, but if I don't connect slave i2c device, this pulse will not happens. Can someone have comment about this? because I have 8 slave i2c device, 7 are read/write OK(also have this pulse), 1 is NG, we are confirm this issue now. We want to know how to make this pulse disappear.  

 

 

Thanks

Ken

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