LPC8N04 i2c Demos from SDK 2.5.0 not working

cameron1 — Sat, 02 Feb 2019 00:36:17 GMT

Hello,

I cannot get the i2c demos in SDK 2.5.0 working for the LPC8N04 (OM40002) demo board.

I have confirmed that I can successfully flash other applications and modify both the polling and interrupt demos with printf statements that indicate they fail to establish an i2c connection via pins 1, 3 and 7 (GND) on P4. I have also tested with 2, 4 and 8 on P3.

Are these demos working for NXP engineers?

Here is my set up:

One OM40002 running "lpc8n04devboard_lpc_i2c_1_interrupt_transfer_master" (or the master polling example)
A second OM40002 running "lpc8n04devboard_lpc_i2c_1_interrupt_transfer_slave" (or the slave polling example)
Wires connecting pins 1, 3 and 7 on P4 on the first board to 1, 3 and 7 on P4 on the second board (per the included doc instructions; also tried 2, 4 and 8 to 2, 4 and 8)
I have tried running the slave first, then the master as well as the master first and then the slave. I've also tried booting both at the same time.
Debugging from both machines I see that the master doesn't get past "Wait for transfer completed." (somewhere around lines 112-120 in the interrupt master example) and the slave doesn't get past "Wait for transfer completed." (somewhere around lines 97-102 in the interrupt slave example)
I have tried with P7 and P8 in SWD mode or GPIO mode, no difference
I am programming with MCUXpressoIDE, both 10.3.0 on a Mac and 10.3.0 on a PC
I am using the built-in debugger on the OM40002
SDK version is 2.5.0 (released 2018-12-17)

Any ideas? See attached for what I understand to be P4 1, 3, 5 and 7, circled in red with pin headers soldered on. I have tried this across 4x different OM40002 boards, no luck.

Re: LPC8N04 i2c Demos from SDK 2.5.0 not working

pmg — Wed, 06 Feb 2019 01:40:04 GMT

Did you add 1k pull-ups to the SDA and SCL lines? There's no mention of this in the example code but pull-ups are usually necessary for I2C.

Re: LPC8N04 i2c Demos from SDK 2.5.0 not working

soledad — Fri, 08 Feb 2019 17:18:09 GMT

Hi,

Like Paul mentioned, there's some issue in the LPC8N04DEV board design, there's no external pull-up on the I2C pins.

Have a nice day!

Regards
Sol

topic Re: LPC8N04 i2c Demos from SDK 2.5.0 not working in LPC Microcontrollers

LPC8N04 i2c Demos from SDK 2.5.0 not working

Re: LPC8N04 i2c Demos from SDK 2.5.0 not working

Re: LPC8N04 i2c Demos from SDK 2.5.0 not working