Content originally posted in LPCWare by pmorrell@1stdetect.com on Thu Mar 19 09:14:33 MST 2015
While I havent physically separated the two halves of the lpc1769 board, I have desoldered the bumps. I made a adapter cabled wired exactly like the EA jtag adapter board that is linked on the page you supplied.
As I said, I have seen the jtag connect twice, but nearly all of the time it can not make a connection. It acts like the TCK is too fast for the processor. Spec says it must be 1/6 of CCLK and CCLK after reset is 4Mhz. Looking at TCK with a scope shows it runs at 1Mhz, and thats 1/4 and not 1/6 of CCLK.
So my question is, is there a way to modify the jtag initialization script to have the TCK run at 500Khz?