I'm having trouble setting up and performing transfers on the I2C1 interface on the LPC1812JET100 microcontroller.
This microcontroller has two I2C interfaces:
One Fast-mode Plus I2C-bus interface with monitor mode and with open-drain I/O pins conforming to the full I2C-bus specification. Supports data rates of up to 1 Mbit/s.
One standard I2C-bus interface with monitor mode and standard I/O pins.
I'm having no trouble setting up and using the full specification, open drain I2C0 port.
I can't seem to setup and execute a transfer to devices on the I2C1 port. I realize that this is not a standard open-drain I2C port but I could not find any information on the use of I2C pullups on this port. So, I put 3.65Kohm pullups on each I2C1_SCL and I2C1_SDA signal line.
I setup the Port 2_3 SDA signal line as Function 1 and enabled the input buffer. I setup the Port 2_4 SCL line as Function 1. I have set pullup and pulldown resistors on both ports as disabled since I have external pullups on these lines.
When I try to do a transfer on the I2C1 bus I get no signal transitions on the I2C1 signals. This seems to indicate that I don't have the pins setup correctly. I searched through the forums and LPCOpen software for example setup code but I was I was not able to find any suggested setups for I2C1 pins.
This is a really critical interface for my product and our product launch is approaching. The devices on this bus are a NXP GPIO Expander and a I2C serial EEPROM.
Thanks in advance for your help.