JTAG/SWD and reset script selection

Discussion created by lpcware Employee on Jun 15, 2016
Latest reply on Jun 15, 2016 by lpcware
Content originally posted in LPCWare by g_mocken on Thu Jun 18 01:46:19 MST 2015

I have some problems in bringing up a custom board featuring an LPC 4074 FB 080.

For testing, I created an "LPCXpresso C Project" via the wizard, selecting "LPC407x_8x - LPCOpen-C Project", the LPC4074 and "lpc_chip_0xx" for the chip library (no board library, yet). Then I built and selected Debug from the Quickstart Panel to create a reasonable default debug configuration.

Results are confusing: I believe that the 4074 supports JTAG, but with JTAG (and LPCLink2 as debug probe) I run into "RedlinkAPI: Hardware interface transfer error". If I switch to SWD, I can program the flash successfully, though.
However, debugging does not start using the default configuration. If I additionally select a reset script like "LPC18LPC43InternalFLASHBootResetscript.scp", then only the debugger starts correctly, and I can perform some single steps.

I would have expected JTAG to work, and the reset script not to work, because according to its name, it is designed for another type of CPU. Should I carry on regardless (using SWD only) or should I suspect some HW related issue?

I have to emphasize that it's a (first!) prototype board, therefore I would like to fix all potential HW issues before going into production.