rp2040-rescue.cfg

source [find target/swj-dp.tcl]
source [find mem_helper.tcl]

set _CHIPNAME rp2040
set _CPUTAPID 0x01002927
set _ENDIAN little

swj_newdap $_CHIPNAME.rescue_dp cpu -dp-id $_CPUTAPID -instance-id 0xf
set _TARGETNAME_0 $_CHIPNAME.rescue
dap create $_TARGETNAME_0.dap -chain-position $_CHIPNAME.rescue_dp.cpu -ignore-syspwrupack

# Have to init before we can do dpreg commands
init

# The rescue debug port uses the AP CTRL/STAT bit DBGPWRUPREQ to reset the
# PSM (power on state machine) of the RP2040 with a flag set in the 
# VREG_AND_POR_CHIP_RESET register. Once the reset is released
# (by clearing the DBGPWRUPREQ flag), the bootrom will run, see this flag,
# and halt. Allowing the user to load some fresh code, rather than loading
# the potentially broken code stored in flash

# Clear DBGPWRUPREQ
$_TARGETNAME_0.dap dpreg 0x4 0x00000000

# Verifying CTRL/STAT is 0
$_TARGETNAME_0.dap dpreg 0x4

echo "Now attach a debugger to your RP2040 and load some code"