whc2001

CC2652 unbricking with Raspberry Pi and OpenOCD

I was a bit quick when flashing my generic CC2652R and ended up dowloading and flashing firmware for CC2652P.. Since it was the wrong firmware, the bootloader also didn't work anymore, making me unable to flash the correct firmware with the integrated USB serial programmer.

Luckily the module has a cJTAG debugging interface, that should make it possible to flash directly onto the chip without the bootloader. But I don't have any serial debuggers, so I have had to come up withj my own from various limited information I could find.

Approach

Using OpenOCD we can use a Raspberry Pi as a JTAG debugger. It does not support cJTAG for debugging, so it will instead send a signal to make the CC2652 switch to normal JTAG. We will then have to connect a few additional cables to the TDO and TDI pins for a full 4-pin JTAG connection.

Shutdown Raspberry Pi with a Single Button

There are two methods:

Scripted Method
Boot Overlay Method (also below as "tl;dr")

tl;dr Version

Add the following to your /boot/config.txt and reboot:

JS

function noteToFreq(note) {
    let a = 440; //frequency of A (coomon value is 440Hz)
    return (a / 32) * (2 ** ((note - 9) / 12));
}

PHP

function noteToFreq($note) {

	interface bcm2835gpio

	bcm2835gpio_peripheral_base 0xFE000000

	# Transition delay calculation: SPEED_COEFF/khz - SPEED_OFFSET
	# These depend on system clock, calibrated for stock 700MHz
	# bcm2835gpio_speed SPEED_COEFF SPEED_OFFSET
	bcm2835gpio_speed_coeffs 236181 60

	# Each of the JTAG lines need a gpio number set: tck tms tdi tdo

	//found this code here
	//https://gist.github.com/speters/f889faec42b510052a6ab4be437d38ca

	//Purpose is to simply run a memory check on ATMEGA238P to test for counterfeit parts

	#include <avr/boot.h>
	#define SIGRD 5
	void setup() {
	// put your setup code here, to run once:
	Serial.begin(115200);

	# Disable any form of screen saver / screen blanking / power management
	xset s off
	xset s noblank
	xset -dpms

	# Allow quitting the X server with CTRL-ATL-Backspace
	setxkbmap -option terminate:ctrl_alt_bksp

	# Start Chromium in kiosk mode
	sed -i 's/"exited_cleanly":false/"exited_cleanly":true/' ~/.config/chromium/'Local State'

	#!/bin/bash

	# This script subscribes to a MQTT topic using mosquitto_sub.
	# On each message received, you can execute whatever you want.

	while true # Keep an infinite loop to reconnect when connection lost/broker unavailable
	do
	mosquitto_sub -h "127.0.0.1" -t "test" \| while read -r payload
	do
	# Here is the callback to execute whenever you receive a message:

	"""
	Copyright 2019 Jason Hu <awaregit at gmail.com>
	Modified 2020 Matthew Hilton <[email protected]>
	Refactor and Modernised 2025 Matthew Hilton <[email protected]>

	Licensed under the Apache License, Version 2.0 (the "License");
	you may not use this file except in compliance with the License.
	You may obtain a copy of the License at

	http://www.apache.org/licenses/LICENSE-2.0

	// ==UserScript==
	// @name Youtube-click-OK
	// @namespace http://tampermonkey.net/
	// @version 0.0.1
	// @description clicks YES on "Video paused. Continue watching?" dialog
	// @author goran
	// @match https://www.youtube.com/*
	// @grant none
	// ==/UserScript==

	[Unit]
	Description=vlmcsd
	Wants=network.target
	After=syslog.target

	[Service]
	Type=forking
	PIDFile=/var/run/vlmcsd.pid
	ExecStart=/usr/local/vlmcsd/vlmcsd -l /var/log/vlmcsd.log -p /var/run/vlmcsd.pid