ESP32

Introduction

As the little grey cells get older probably time to give to pointers to myself

Pinout for ESP32

This is the pinout for my ESP32

UDEV

To make sure the device is recogised we need to add rules to /etc/udev/rules.d/

This is my board and my UART interface. The plugdev is the important bit as we need to not run things as root for some strange reason.

ATTRS{idVendor}=="0403", ATTRS{idProduct}=="6001", MODE="660", GROUP="plugdev", TAG+="uaccess"
ATTRS{idVendor}=="10c4", ATTRS{idProduct}=="ea60", MODE="660", GROUP="plugdev", TAG+="uaccess"

openocd and FT232R

User Manual

This can be found [here]

FT232

This is what I believe my FT232 is [here]

The connector shown for a similar board gives

Connecting

The following was suggested to get the JTAG interface to work.

GPIO15=TDO
GPIO12=TDI
GPIO13=TCK
GPIO14=TMS
GND=GND

ft232r.cfg

This is what I have used for ft232.cfg

interface ft232r

adapter_khz 3000

ft232r_tck_num TXD
ft232r_tdi_num RXD 
ft232r_tdo_num RI
ft232r_tms_num CTS
ft232r_trst_num DTR
ft232r_srst_num DCD

Running Open OCD

The scripts are written in TCL. Here is the command to run

cd ~/.espressif/tools/openocd-esp32/v0.10.0-esp32-20210401/openocd-esp32/bin
./openocd  -d3   -f ../share/openocd/scripts/interface/ft232r.cfg -f ../share/openocd/scripts/board/esp-wroom-32.cfg

Distilled Script

I have worked through the scripts provided with openocd and this is the script I believe is run from the above command.

interface ft232r
#ft232r_restore_serial 0x15

ft232r_tdi_num TXD
ft232r_tck_num DTR
ft232r_tdo_num RXD
ft232r_tms_num CTS
# trst/srst are not used but must have different values than above
ft232r_trst_num DCD
ft232r_srst_num RI

#reset_config none

adapter_khz 500


set ESP32_FLASH_VOLTAGE 3.3

# ESP_COMMON.CFG

set _FLASH_SIZE "auto"
puts "==== FLASH_SIZE $_FLASH_SIZE"

set _SEMIHOST_BASEDIR "."
puts "==== SEMIHOST_BASEDIR $_SEMIHOST_BASEDIR"


###
### configure_esp_workarea
###
proc configure_esp_workarea { TGT CODE_ADDR CODE_SZ DATA_ADDR DATA_SZ } {
        #WARNING: be careful when selecting working ares for code and data, they should not overlap due to ESP32 physical memory mappings
        $TGT configure -work-area-phys $CODE_ADDR -work-area-virt $CODE_ADDR -work-area-size $CODE_SZ -work-area-backup 1
        # since ESP32 cannot use single address space for code and data we need additional working area to keep data
        $TGT configure -alt-work-area-phys $DATA_ADDR -alt-work-area-virt $DATA_ADDR -alt-work-area-size $DATA_SZ -alt-work-area-backup 1
}


###
### configure_esp_workarea
###
proc configure_esp_flash_bank { TGT DRV SIZE } {
        set _SIZE SIZE
	# special value for flash driver
        set _SIZE 0

        # whole flash for programming purposes
        # TODO: remove it when support for GDB's 'load' comand is implemented
        flash bank $TGT.flash $DRV 0x0 $_SIZE 0 0 $TGT
        # So define mapped flash regions as separate flashes
        # OOCD creates memory map using registered flash banks
        flash bank $TGT.irom $DRV 0x0 0 0 0 $TGT
        flash bank $TGT.drom $DRV 0x0 0 0 0 $TGT
}

# ESP32.cfg 

# The ESP32 only supports JTAG.
# transport select jtag

# Target specific registers
set EFUSE_BLK0_RDATA1_REG 0x3ff5A004

set _CHIPNAME esp32
puts "==== CHIPNAME $_CHIPNAME"

set _CPUTAPID 0x120034e5
puts "==== CPUTAPID $_CPUTAPID"

set _ONLYCPU 3
puts "==== ONLYCPU $_ONLYCPU"

set _FLASH_VOLTAGE $ESP32_FLASH_VOLTAGE
puts "==== FLASH_VOLTAGE $_FLASH_VOLTAGE"

set _CPU0NAME cpu0
set _CPU1NAME cpu1
set _TARGETNAME_0 $_CHIPNAME.$_CPU0NAME
set _TARGETNAME_1 $_CHIPNAME.$_CPU1NAME

set _RTOS "FreeRTOS"
puts "==== RTOS $_RTOS"


jtag newtap $_CHIPNAME $_CPU0NAME -irlen 5 -expected-id $_CPUTAPID
jtag newtap $_CHIPNAME $_CPU1NAME -irlen 5 -expected-id $_CPUTAPID

target create $_TARGETNAME_0 $_CHIPNAME -endian little -chain-position $_TARGETNAME_0 -coreid 0 -rtos $_RTOS
configure_esp_workarea $_TARGETNAME_0 0x40090000 0x3400 0x3FFC0000 0x10000
configure_esp_flash_bank $_TARGETNAME_0 $_CHIPNAME $_FLASH_SIZE

# APP-CPU
target create $_TARGETNAME_1 $_CHIPNAME -endian little -chain-position $_TARGETNAME_1 -coreid 1 -rtos $_RTOS
configure_esp_flash_bank $_TARGETNAME_1 $_CHIPNAME $_FLASH_SIZE
target smp $_TARGETNAME_0 $_TARGETNAME_1


$_TARGETNAME_0 esp32 flashbootstrap $_FLASH_VOLTAGE
$_TARGETNAME_0 xtensa maskisr on
$_TARGETNAME_0 xtensa smpbreak BreakIn BreakOut
$_TARGETNAME_0 esp semihost_basedir $_SEMIHOST_BASEDIR

$_TARGETNAME_1 configure -event gdb-attach {
    $_TARGETNAME_1 xtensa smpbreak BreakIn BreakOut
    # necessary to auto-probe flash bank when GDB is connected
    halt
}
puts "==================================== Scooby doo 1"