ESP8266 Community Forum

- Thu Mar 16, 2017 12:39 pm #63800 Hello,

We have a PCB with ESP8266 and 1MB flash memory, which looks from flash datasheet like it does not support dual and quad SPI modes (only standard mode).
We were able to write the flash memory, read and compare the firmware in boot mode and it is OK, but when using ESP8266 not in bootloader mode there is no command prompt, comparing to usage of bought ESP module with same burnt NodeMCU firmware, which gives the command prompt and works as expected.

Question: Is ESP8266 able to run code from standard SPI flash (in our case it is Adesto Technologies AT25DF081A-SH-B)?

Thank you in advance!

Best regards,
Dima.

- Thu Mar 16, 2017 2:52 pm #63808 I looked at the specs of the chip you mentioned, and it seems to support DIO.

- Thu Mar 16, 2017 5:21 pm #63815 Hello,
Thank you for quick response!
If the AT25DF081A flash has dual mode, could it be that the problem is that it has no quad mode?
We tried to solder ' Adesto Technologies AT25DF081A-SH-B' to working ESP module instead of its original flash, the results were very similar - we were able to write/read firmware in bootloader mode, but no command prompt in UART mode. We only saw some output from ESP8266, which was unreadable ASCII chars, like improper setting of baud rate.
After measurement bit width 17.33uS by scope, we set the baud rate to 57600, but stil set of unreadable chars. Same result with two Adesto's chips.
We did not check same test in reverse direction by soldering flash from ESP module to our board, because we have 150 mil SOIC-8 footprint, as AT25DF081A has that fits ESP module, but flash on ESP module Berg BG25Q80A 208 mil SOIC does not fit our board's footprint.

Thank you!
Best regards,
Dima.

- Fri Mar 17, 2017 9:14 am #63843 Be aware that your firmware binary should have proper bits set in its header to let the bootloader knows which mode you are running. If those bits are not set properly, it could still try to boot in QIO, which is not available.
http://esp8266-re.foogod.com/wiki/SPI_Flash_Format
SOICW can still fit on SOIC pad if you bend the pins properly and having good soldering skills.