LPC 1788 with SC18IS606 I2C communication

[dimoftedenisa]

Hello,

I'm trying to use LPC1788 OEM board together with SC18IS606 circuit via I2C bus.

For I2C bus i am using LPCOPEN drivers, the latest version. Also, in my application i am using LWIP stack for an ethernet communication and an UART connection. These other two communication types are working fine, but i have an issue on I2C bus.

I2C signals are connected to pin 108 (I2C0_SCL) and pin 109 (I2C0_SDA) from OEM board. In application i setup these signals to P5[2] and P5[3] with IOCON_FUNC5 and I initialized I2C0 to work in polling mode with 100 kHz speed. I2C slave address is 0x50. 

My issue is that after i send a first command to SC18IS606, SDA and SCL goes to LOW and I can not send another command on I2C bus. I can not figure out what is happening because I used in past the same LPC1788 OEM board and I2C LPCOpen drivers with another circuit, TMP422 and everything worked fine.

After I2C is initialized, I wrote to SC18IS606 to send me the version (0xFE function id), but after the command is sent, I2C bus is stuck.

Of course I want to use this circuit for I2C to SPI bridge. But after first command (does not matter what command is sent - SPI configuration, Idle command, Read version command), SDA and SCL goes to LOW state even if I have pullup rezistor on these lines.

Thank you,

Denisa

[Alice_Yang]

Hello @dimoftedenisa 

Recommend you first use a project only includes I2C, without  ethernet communication and an UART connection. Then check SC18IS606 datasheet,   use logic analyzer measures the signal, whether it meet the signal sequence DS mentioned. 

BR

Alice