Help with possible faulty ESP32?

[Eric Svedberg]

Hello all,

I'm very late to the game in putting my IMSAI8080 together.  After starting assembly, I've gotten to the first test step and things don't look good.  My ESP32 just keeps restarting after an esp_image checksum failure.  Here's what I get when I hook a terminal up to the USB.  I removed the uSD card, same thing.  I checked all of my soldering and there are no mistakes, no pins are crossed, etc., that I can find.  I've removed the ESP32 from the board and still get this same output, so I don't think it's my board.

ets Jun 8 2016 00:22:57

rst:0x3 (SW_RESET),boot:0x3f (SPI_FAST_FLASH_BOOT)
configsip: 188777542, SPIWP:0xee
clk_drv:0x00,q_drv:0x00,d_drv:0x00,cs0_drv:0x00,hd_drv:0x00,wp_drv:0x00
mode:DIO, clock div:1
load:0x3fff0018,len:4
load:0x3fff001c,len:4524
load:0x40078000,len:13468
ho 0 tail 12 room 4
load:0x40080400,len:3784
entry 0x40080620
ets Jun 8 2016 00:22:57

rst:0x1 (POWERON_RESET),boot:0x3f (SPI_FAST_FLASH_BOOT)
configsip: 188777542, SPIWP:0xee
clk_drv:0x00,q_drv:0x00,d_drv:0x00,cs0_drv:0x00,hd_drv:0x00,wp_drv:0x00
mode:DIO, clock div:1
load:0x3fff0018,len:4
load:0x3fff001c,len:4524
load:0x40078000,len:13468
ho 0 tail 12 room 4
load:0x40080400,len:3784
entry 0x40080620
E (308) esp_image: Checksum failed. Calculated 0xdc read 0xd8
E (308) boot: Factory app partition is not bootable
E (309) esp_image: image at 0x110000 has invalid magic byte
E (315) boot_comm: mismatch chip ID, expect 0, found 65535
E (321) boot_comm: can't run on lower chip revision, expect 1, found 255
E (329) boot: OTA app partition slot 0 is not bootable
E (334) esp_image: image at 0x210000 has invalid magic byte
E (341) boot_comm: mismatch chip ID, expect 0, found 65535
E (347) boot_comm: can't run on lower chip revision, expect 1, found 255
E (354) boot: OTA app partition slot 1 is not bootable
E (360) boot: No bootable app partitions in the partition table

I thought maybe re-flashing the ESP32 would be a next step.  But, I can't seem to get the esptool.py scripts to connect to it.  If I try and read the flash memory, I get the same connection problem.

Bradbury:~ ericsvedberg$ esptool.py -p /dev/cu.usbserial-10 -b 115200 read_flash 0 0x200000 ~/flash_contents.bin
esptool.py v3.1
Serial port /dev/cu.usbserial-10
Connecting........_____....._____....._____....._____....._____....._____....._____

A fatal error occurred: Failed to connect to Espressif device: Timed out waiting for packet header
Bradbury:~ ericsvedberg$

Also, even if I was to flash the imsaisim_esp32.bin file, I'm not sure what starting address to write it to.  I can't find any concrete documentation on how to "start over".

Lastly, maybe my PICO is just broken?

Any help appreciated...

eric

[aga...@gmail.com]

Eric,

It's been a while since your post, perhaps you've already solved this. Instructions for flashing the pico are on the github, latest release, within the FIRMWARE package. File is FLASHING.md.

It looks like you're using a Mac, I don't have one of those so can't help with this but make sure you've identified the port correctly under the /dev tree.

ted

[Eric Svedberg]

Hi Ted,

Thanks for the response.  I appreciate it!

I wasn't able to connect to the ESP32, so I don't think I can flash it.  I think it's toast.  I can't connect to it to check the fuses with espefuse.py, which should be set for 3.3v, but ...

I did however receive a new ESP32 yesterday from Jameco.  I was able to flash it with the FIRMWARE package and things are looking good now.  I've got my LEDs in and all of the chips.  I just need to read up on the reinforcement things that I've seen mentioned.  Not sure what those are or why they're needed.  My circuit board sure is warped though, it's kinda like a banana on the workbench.

eric