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Last updated: 16 Sep 2020
GR-PEACH is an Mbed enabled platform which combines the advantages of the Mbed ecosystem and Arduino UNO form factor.

unable to halt cpu using JLink

Topic last updated 21 Nov 2019, by Jonathan Pickett. 1 reply
James Agerton
10 Nov 2019

I'm using a JLink EDU Mini to try to program a new kernel onto the GR-Peach as a test board. However, when I try to halt the cpu with JLinkExe I get: WARNING: CPU not halted after Reset, halting using Halt request. I don't believe my JLink is properly halting the cpu.

I shorted the R29 resistor to connect the Pin 10 of the JTAG interface. I've also replaced the firmware with an older version as a more recent version was preventing connection at all.

The Halt command returns a list of registers, but I don't know if that reflects whether or not it has been successful. Here's the output on the Linux Terminal: J-Link>halt PC: (R15) = 180087AA, CPSR = 000000BF (System mode, THUMB IRQ dis.) Current: R0 =00000001, R1 =00000002, R2 =00000001, R3 =00000000 R4 =20020058, R5 =00000000, R6 =00000000, R7 =00000000 R8 =00000000, R9 =00000000, R10=00000000, R11=00000000, R12=00000000 R13=00000000, R14=00000000 USR: R8 =00000000, R9 =00000000, R10=00000000, R11=00000000, R12=00000000 R13=20022A40, R14=1800A597 FIQ: R8 =00000000, R9 =00000000, R10=00000000, R11=00000000, R12=00000000 R13=208FFE00, R14=00000000, SPSR=EA0263C1 IRQ: R13=208FFD00, R14=18008496, SPSR=4000003F SVC: R13=208F0D00, R14=18008E94, SPSR=6000003F ABT: R13=208FFF00, R14=00000000, SPSR=D205BCB1 UND: R13=20900000, R14=1800BBD4, SPSR=6000003F

Jonathan Pickett
21 Nov 2019

I just got this working. My setup is:

1. J-Link Pro. J-Link software is V6.54c. 2. GR-Peach with firmware upgrade found at https://armmbed.github.io/DAPLink/?board=GR_PEACH. Short out JP2 while booting to get into firmware upgrade mode. Reboot.

When connecting the Segger, power the board from the USB0 interface, rather than the mbed USB port. Once in a debug session with the Segger, you can plug in a cable to the mbed USB port so you can get to the virtual COM port for the debug spew.