Using LPC8N04 Expansion Headers P3/P4 for I2C

[jameswhitney]

Greetings,

I had a question on using the expansion headers P3, or P4 on the LPC8N04. In the Dev. Board User's Guide, it says that to use the SDA/SCL lines the board must be separated into the DP/MP sections. However, when I read the 'readme' file for the i.e., I2C Polling Transfer Master, it makes no mention of having to separate the two sections. My questions are:

1 - Do I need to separate the boards or not, to use the SDA and SCL signals ?

2 - If I do have to separate the boards and I want to use the on-board debugger should I use 'P3' ?

3 - Once the boards are separated, how does the MP side get programmed (if not using NFC) ?

Regards,

J.

[jameswhitney]

OK,

Wired up the P4 connector *without* separating the DP and MP sections. Everything worked fine.

Thanks,

Jim

[xiangjun_rong]

Hi, James,

I do not think you have to separate the board into the DP/MP sections in order to use SCL and SDA I2C module for LPC8No4 board(OM40002 board).

If you have I2C device, you can connect the PIO0_4_SCL/PIO0_5_SDA signal from the P4 or P3 connector to the device with external pull-up resistors, it is okay.

As you know that the PIO0_4_SCL/PIO0_5_SDA  are connected to cathode of LED array, but I do not think it will take effect on the data transfer.

Hope it can help you

BR

XiangJun Rong

[jameswhitney]

XiangJun,

I will give it a try; just wanted to minimize my chance of blowing up the board !

Jim