SPI SRAM memory test fail

[internetspeedbump]

Hi, my IMSAI 8080 replica has not been working for a while and I finally got around to having a look at it.

Connected to the USB port, it constantly reboots, complaining about the SPI SRAM

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ELF file SHA256: a195df7f0fdfe351

Rebooting...
ets Jun 8 2016 00:22:57

rst:0xc (SW_CPU_RESET),boot:0x3f (SPI_FAST_FLASH_OOT)
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:0x3fff0030,len:4940
ho 0 tail 12 room 4
load:0x40078000,len:15120
load:0x40080400,len:3764
entry 0x40080620
I (307) psram: This chip is ESP32-PICO
I (307) spiram: Found 64Mit SPI RAM device
I (307) spiram: SPI RAM mode: flash 80m sram 80m
I (310) spiram: PSRAM initialized, cache is in low/high (2-core) mode.
I (317) cpu_start: Pro cpu up.
I (321) cpu_start: Starting app cpu, entry point is 0x40081c60
I (313) cpu_start: App cpu up.
E (812) spiram: SPI SRAM memory test fail. 129763/131072 writes failed, first @ 3F800000

E (812) cpu_start: External RAM failed memory test!

abort() was called at PC 0x40081d94 on core 0

acktrace: 0x40082712:0x3ffe3bb0 0x4008ed79:0x3ffe3bd0 0x400986b2:0x3ffe3bf0 0x40081d94:0x3ffe3c60 0x400793da:0x3ffe3c90 |<-CORRUPTED

[internetspeedbump]

Also... As part of my troubleshooting I upgraded the board to the latest firmware using the esptools.

[dmcnaugh]

I have had a PSRAM module fail in the past but not for a long time time.

So you have options:

• you can replace the PSRAM IC with a new one, https://mouser.com/ProductDetail/878-APS6404L-3SQR-SN
• if that is a problem to source then I have some but it will take time to arrive in the post to you
• alternatively, you can remove the PSRAM IC and the accompanying resistor and capacitor and source the ESP32-PICO module I am now supplying https://mouser.com/ProductDetail/356-ESP32PCODEVKITM2
  • this has the PSRAM onboard
  • but you will have to program the ESP32 module yourself using the esptool.py from Espressif, following the directions I provide with the firmware download

[internetspeedbump]

Hi, Thanks for the response and part numbers. I opted for the ESP32-PICO-DevKitM-2 instead of the PSRAM because it was available next day from Amazon rather than having to wait for Mouser. However, I notice that the new board has fewer pins than the old one. I see that the power and ground are the same at the usb side of the package, but they differ after that. Do I just plug it in at the usb side and let the last pins be empty? Is there some sort of pin remapping that needs to be done? Thanks for your help and the great kit. I bought it in 2020 and It’s been working well until lately. Thanks, Peter

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On Jan 17, 2025, at 3:10 PM, TheHighNibble ***@***.***> wrote: I have had a PSRAM module fail in the past but not for a long time time. So you have options: you can replace the PSRAM IC with a new one, https://mouser.com/ProductDetail/878-APS6404L-3SQR-SN if that is a problem to source then I have some but it will take time to arrive in the post to you alternatively, you can remove the PSRAM IC and the accompanying resistor and capacitor and source the ESP32-PICO module I am now supplying https://mouser.com/ProductDetail/356-ESP32PCODEVKITM2 this has the PSRAM onboard but you will have to program the ESP32 module yourself using the esptool.py from Espressif, following the directions I provide with the firmware download — Reply to this email directly, view it on GitHub <#188 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AI6QI736WYES7KYL53VGEFD2LGEWFAVCNFSM6AAAAABVBPU3IWVHI2DSMVQWIX3LMV43URDJONRXK43TNFXW4Q3PNVWWK3TUHMYTCOBXGIZDSMY>. You are receiving this because you authored the thread.

[internetspeedbump]

I replaced the PSRAM chip and it's all working again. Thanks for the help