LPC1768 Chain programming issue, in uVision using SEGGER

Discussion created by lpcware Employee on Jun 15, 2016
Content originally posted in LPCWare by rsameni on Mon Dec 02 12:26:44 MST 2013

I have customized board with two LPC1768, which pass data to each other via SPI. The problem I have is with their JTAG chain programming. When I program one of them the other one is also (usually) programmed; but the behavior is not very deterministic. I have all the recommended pull-ups and pull-downs required on the JTAG wires and the two MCU work with the same clock oscillator. Therefore, no additional seems to be required. I use the uVision Keil software + SEGGER for programming. SEGGER detects both devices on the chain and doesn't give any errors when I program them.

I've seen a rather old post on this, which was unanswered on SEGGER's forum: JTAG chain - 3 LPC1768 on board

Does anyone have a clue? Is there any special software setting required?