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Table of Contents
Raspberry Pi PICO
Dual core Arm Cortex-M0 microcontroller designed to run MicroPython.
There are four varieties of PICO version 1 board produced by RPi. The differences are whether they come pre-installed with header pins and a debug socket and if they have a WiFi adapter on board.
Bootloader
Entry to the bootloader occurs when either the flash is empty or the BOOTSEL button is depressed when plugging in the device.
Mounting the drive will gain access to firmware upload.
mount /dev/sda1 /mnt cat /mnt/INFO_UF2.TXT
RP2040-B1
UF2 Bootloader v2.0 Model: Raspberry Pi RP2 Board-ID: RPI-RP2
RP2040-B2
UF2 Bootloader v3.0 Model: Raspberry Pi RP2 Board-ID: RPI-RP2
UF2 Bootloader v3.0 Model: Raspberry Pi RP2 Board-ID: RPI-RP2
SDK
apt install build-essential git pkg-config libusb-1.0-0-dev cmake
mkdir -p /opt cd /opt git clone https://github.com/raspberrypi/pico-sdk cd pico-sdk git submodule update --init
setenv PICO_SDK_PATH /opt/pico-sdk
FreeRTOS
cd /opt git clone https://github.com/FreeRTOS/FreeRTOS-Kernel
setenv FREERTOS_KERNEL_PATH /opt/FreeRTOS-Kernel
Picotool
This tool is used to convert ELF binaries into UF2 objects to upload to the PICO. and to inspect running firmware via the bootloader.
mkdir -p /opt/src cd /opt/src git clone https://github.com/raspberrypi/picotool cd picotool git submodule update --init mkdir build cd build cmake .. make make install
cp /opt/src/picotool/udev/99-picotool.rules /etc/udev/rules.d udevadm control --reload-rules udevadm trigger
Picotool can show flash info when in bootloader mode.
Below are two PICOs which contain no firmware and one other running debugprobe.
picotool info -a
Multiple RP2040 devices in BOOTSEL mode found:
Device at bus 1, address 37:
----------------------------
Program Information
none
Fixed Pin Information
none
Build Information
none
Device Information
type: RP2040
revision: B2
Device at bus 1, address 40:
----------------------------
Program Information
none
Fixed Pin Information
none
Build Information
none
Device Information
type: RP2040
revision: B2
Device at bus 1, address 41:
----------------------------
Program Information
name: debugprobe
features: PROBE UART BAUDRATE 115200
PROBE UART INTERFACE uart1
UART stdin / stdout
binary start: 0x10000000
binary end: 0x10009f70
Fixed Pin Information
0: UART0 TX, UART0 TX
1: UART0 RX, UART0 RX
2: PROBE SWCLK
3: PROBE SWDIO
4: PROBE UART TX
5: PROBE UART RX
25: LED
Build Information
sdk version: 2.0.0
pico_board: pico
build date: Aug 23 2024
build attributes: Release
Device Information
type: RP2040
revision: B1
flash size: 2048K
flash id: 0xE66038B7135F7437
Reboot firmware on specific device
picotool reboot --bus 1 --address 41
Debugprobe
Debugprobe turns a Pi PICO into a debugger which can then be used to debug another Pi PICO.
This project was previously known as picoprobe and the difference would appear to be change in protocol from picoprobe to cmsis-dap as the interface when using OpenOCD.
This is cheap alternative to buying a dedicated debugger.
Notice: On the Pi Pico revision B1 the probe will disconnect from the USB bus and lock up with using its UART feature. This was seen on a Pi 4B host. This fault has not been seen with using revision B2 Pico.
Debug probe depends on GCC-ARM and Picotool to build from source.
cd /opt/src/ git clone https://github.com/raspberrypi/debugprobe cd debugprobe git submodule update --init
debugprobe
The debugprobe is also a dedicated hardware device which uses a PI PICO.
Build and copy debugprobe.uf2 to the debugprobe device.
cd /opt/src/debugprobe mkdir debugprobe cd debugprobe cmake .. make
Pi PICO
A regular PI PICO as a debugger has its own firmware.
Build and copy debugprobe_on_pico.uf2 to a Pi PICO device.
cd /opt/src/debugprobe mkdir debugprobe_on_pico cd debugprobe_on_pico cmake -DDEBUG_ON_PICO=1 .. make
USB
usb 1-1.1: new full-speed USB device number 5 using dwc_otg usb 1-1.1: New USB device found, idVendor=2e8a, idProduct=000c, bcdDevice= 2.01 usb 1-1.1: New USB device strings: Mfr=1, Product=2, SerialNumber=3 usb 1-1.1: Product: Debugprobe on Pico (CMSIS-DAP) usb 1-1.1: Manufacturer: Raspberry Pi usb 1-1.1: SerialNumber: E66038B7135F7437 cdc_acm 1-1.1:1.1: ttyACM0: USB ACM device usbcore: registered new interface driver cdc_acm cdc_acm: USB Abstract Control Model driver for USB modems and ISDN adapters
OpenOCD
Wiring
debubprobe_on_Pico GND Target Pico GND debugprobe_on_Pico GP2 Target Pico SWCLK debugprobe_on_Pico GP3 Target Pico SWDIO debugprobe_on_Pico GP4/UART1 TX Target Pico GP1/UART0 RX debugprobe_on_pico GP5/UART1 RX Target Pico GP0/UART0 TX
Debug
openocd -f "interface/cmsis-dap.cfg" -f "target/rp2040.cfg" -c "adapter speed 5000"
Open On-Chip Debugger 0.12.0+dev-00683-gac63cd00d (2024-08-24-12:37)
Licensed under GNU GPL v2
For bug reports, read
http://openocd.org/doc/doxygen/bugs.html
Info : Hardware thread awareness created
Info : Hardware thread awareness created
adapter speed: 5000 kHz
Info : Listening on port 6666 for tcl connections
Info : Listening on port 4444 for telnet connections
Info : Using CMSIS-DAPv2 interface with VID:PID=0x2e8a:0x000c, serial=E66038B7135F7437
Info : CMSIS-DAP: SWD supported
Info : CMSIS-DAP: Atomic commands supported
Info : CMSIS-DAP: Test domain timer supported
Info : CMSIS-DAP: FW Version = 2.0.0
Info : CMSIS-DAP: Interface Initialised (SWD)
Info : SWCLK/TCK = 0 SWDIO/TMS = 0 TDI = 0 TDO = 0 nTRST = 0 nRESET = 0
Info : CMSIS-DAP: Interface ready
Info : clock speed 5000 kHz
Info : SWD DPIDR 0x0bc12477, DLPIDR 0x00000001
Info : SWD DPIDR 0x0bc12477, DLPIDR 0x10000001
Info : [rp2040.core0] Cortex-M0+ r0p1 processor detected
Info : [rp2040.core0] target has 4 breakpoints, 2 watchpoints
Info : [rp2040.core0] Examination succeed
Info : [rp2040.core1] Cortex-M0+ r0p1 processor detected
Info : [rp2040.core1] target has 4 breakpoints, 2 watchpoints
Info : [rp2040.core1] Examination succeed
Info : [rp2040.core0] starting gdb server on 3333
Info : Listening on port 3333 for gdb connections
Program
#! /bin/bash
if test $# -ne 1; then
echo "missing arg"
exit 1
fi
ELF=$1
openocd -f "interface/cmsis-dap.cfg" -f "target/rp2040.cfg" -c "adapter speed 5000" \
-c "program $ELF preverify verify reset exit"
Examples
cd /opt/src git clone https://github.com/raspberrypi/pico-examples cd pico-examples mkdir build cd build cmake .. make
cd /opt/src/pico-examples/build/blink
openocd -f "interface/cmsis-dap.cfg" -f "target/rp2040.cfg" -c "adapter speed 5000" -c "program blink.elf preverify verify reset exit"
Open On-Chip Debugger 0.12.0-00024-g34afaa939 (2024-08-26-02:18) [https://github.com/STMicroelectronics/OpenOCD]
Licensed under GNU GPL v2
For bug reports, read
http://openocd.org/doc/doxygen/bugs.html
adapter speed: 5000 kHz
Info : Using CMSIS-DAPv2 interface with VID:PID=0x2e8a:0x000c, serial=E66038B7135F7437
Info : CMSIS-DAP: SWD supported
Info : CMSIS-DAP: Atomic commands supported
Info : CMSIS-DAP: Test domain timer supported
Info : CMSIS-DAP: FW Version = 2.0.0
Info : CMSIS-DAP: Interface Initialised (SWD)
Info : SWCLK/TCK = 0 SWDIO/TMS = 0 TDI = 0 TDO = 0 nTRST = 0 nRESET = 0
Info : CMSIS-DAP: Interface ready
Info : clock speed 5000 kHz
Info : SWD DPIDR 0x0bc12477, DLPIDR 0x00000001
Info : SWD DPIDR 0x0bc12477, DLPIDR 0x10000001
Info : [rp2040.core0] Cortex-M0+ r0p1 processor detected
Info : [rp2040.core0] target has 4 breakpoints, 2 watchpoints
Info : [rp2040.core1] Cortex-M0+ r0p1 processor detected
Info : [rp2040.core1] target has 4 breakpoints, 2 watchpoints
Info : starting gdb server for rp2040.core0 on 3333
Info : Listening on port 3333 for gdb connections
Info : starting gdb server for rp2040.core1 on 3334
Info : Listening on port 3334 for gdb connections
[rp2040.core0] halted due to debug-request, current mode: Thread
xPSR: 0xf1000000 pc: 0x000000ea msp: 0x20041f00
[rp2040.core1] halted due to debug-request, current mode: Thread
xPSR: 0xf1000000 pc: 0x000000ea msp: 0x20041f00
**pre-verifying**
Error: checksum mismatch - attempting binary compare
** Programming Started **
Info : Found flash device 'win w25q16jv' (ID 0x001540ef)
Info : RP2040 B0 Flash Probe: 2097152 bytes @0x10000000, in 32 sectors
Info : Padding image section 1 at 0x100019ec with 20 bytes (bank write end alignment)
Warn : Adding extra erase range, 0x10001a00 .. 0x1000ffff
** Programming Finished **
** Verify Started **
** Verified OK **
** Resetting Target **
shutdown command invoked
J-Link
Segger J-Link can be use to interact with the PICO via the debug port.
Connect SWCLK, SWDIO and VREF on the target PICO.
CORE 0
echo "exit" | /opt/JLink/JLinkExe -device RP2040_M0_0 -if swd -speed 4000 -autoconnect 1 -nogui 1 SEGGER J-Link Commander V7.82a (Compiled Oct 31 2022 11:25:49) DLL version V7.82a, compiled Oct 31 2022 11:25:22 Connecting to J-Link via USB...O.K. Firmware: J-Link EDU Mini V1 compiled Oct 21 2022 11:17:52 Hardware version: V1.00 J-Link uptime (since boot): 0d 00h 09m 41s S/N: 801011752 License(s): FlashBP, GDB USB speed mode: Full speed (12 MBit/s) VTref=3.259V Device "RP2040_M0_0" selected. Connecting to target via SWD ConfigTargetSettings() start J-Link script: ConfigTargetSettings() ConfigTargetSettings() end Found SW-DP with ID 0x0BC12477 DPIDR: 0x0BC12477 CoreSight SoC-400 or earlier Scanning AP map to find all available APs AP[1]: Stopped AP scan as end of AP map has been reached AP[0]: AHB-AP (IDR: 0x04770031) Iterating through AP map to find AHB-AP to use AP[0]: Core found AP[0]: AHB-AP ROM base: 0xE00FF000 CPUID register: 0x410CC601. Implementer code: 0x41 (ARM) Found Cortex-M0 r0p1, Little endian. FPUnit: 4 code (BP) slots and 0 literal slots CoreSight components: ROMTbl[0] @ E00FF000 [0][0]: E000E000 CID B105E00D PID 000BB008 SCS [0][1]: E0001000 CID B105E00D PID 000BB00A DWT [0][2]: E0002000 CID B105E00D PID 000BB00B FPB Cortex-M0 identified.
CORE 1
echo "exit" | /opt/JLink/JLinkExe -device RP2040_M0_1 -if swd -speed 4000 -autoconnect 1 -nogui 1 SEGGER J-Link Commander V7.82a (Compiled Oct 31 2022 11:25:49) DLL version V7.82a, compiled Oct 31 2022 11:25:22 Connecting to J-Link via USB...O.K. Firmware: J-Link EDU Mini V1 compiled Oct 21 2022 11:17:52 Hardware version: V1.00 J-Link uptime (since boot): 0d 00h 09m 48s S/N: 801011752 License(s): FlashBP, GDB USB speed mode: Full speed (12 MBit/s) VTref=3.260V Device "RP2040_M0_1" selected. Connecting to target via SWD ConfigTargetSettings() start J-Link script: ConfigTargetSettings() ConfigTargetSettings() end Found SW-DP with ID 0x0BC12477 DPIDR: 0x0BC12477 CoreSight SoC-400 or earlier Scanning AP map to find all available APs AP[1]: Stopped AP scan as end of AP map has been reached AP[0]: AHB-AP (IDR: 0x04770031) Iterating through AP map to find AHB-AP to use AP[0]: Core found AP[0]: AHB-AP ROM base: 0xE00FF000 CPUID register: 0x410CC601. Implementer code: 0x41 (ARM) Found Cortex-M0 r0p1, Little endian. FPUnit: 4 code (BP) slots and 0 literal slots CoreSight components: ROMTbl[0] @ E00FF000 [0][0]: E000E000 CID B105E00D PID 000BB008 SCS [0][1]: E0001000 CID B105E00D PID 000BB00A DWT [0][2]: E0002000 CID B105E00D PID 000BB00B FPB Cortex-M0 identified.
