I am afraid it will never work.
I used a simple sketch (attached). NO SPI, NO Serialflash !
If I select any of the GPIO 6 to 11 which are used for flash it will reboot. E.g. selecting pin 10 I get repeatedly:
test of pinmode flash test
Pin selected: 10
ets Jul 29 2019 12:21:46
rst:0x8 (TG1WDT_SYS_RESET),boot:0x13 (SPI_FAST_FLASH_BOOT)
configsip: 0, 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:0x3fff0030,len:1344
load:0x40078000,len:13964
load:0x40080400,len:3600
entry 0x400805f0
If you select another GPIO ( say 2 or 17) it all works.
I found a post on another forum about the SPI_FAST_FLASH_BOOT : Make sure you are NOT using GPIO 6-11 for any purpose and leave these pins floating on your custom board. These pins are connected to the on-board flash and will result in the error you show if you are attempting to use them.
The ESP32 chip on the Micromod is an ESP32-D0WDQ6. The datasheet (https://www.espressif.com/sites/default … eet_en.pdf) has a clear warning about some GPIO’s (including GPIO 6 -11):
allocated for communication with in-package flash/PSRAM and NOT recommended for other uses.
I think it was a design error by Sparkfun and they do not mention the possibility of using the SerialFlash anywhere.
test1.zip (435 Bytes)