How to use SPI NOR flash on a v1.2 Duo

Can I solder a 3.3v SPI NOR flash chip to the 8 pin header on the board? The pinout looks correct for such a chip and there’s 3.3V on the correct power pin. Will the 1.0.5 software notice the chip and make it available as a MTD device or similar?

If not, what type of chip is appropriate for that header.

Thank you!

It’s for EMMC style memory, search for symbol shown on schematics of board.

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Cool, thanks. Any idea if I were to populate it would it be recognized by the current build of Linux?

looks like here:

must be edited

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Thank you. That looks oddly like SDIO connected WiFi, but it might be worth a try. I wonder if I can connect another uSD card to these signals. That might be a bit easier to do. It would be an interesting test at least.

Thanks again for your help.

On V1.2, it is SD NAND, and the IOB board can be welded with NOR FLASH W25Q256, which is usable. But to use NAND FLASH W25N01, a resistor needs to be welded, but the official tag number map has not been released

I’m looking at v1.2 schematic and I’m confused.
It shows connections which are parallel with SD slot.
I ask if to be sure I cannot use soldered SD NAND and SD card simultanously?

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No you cannot use both. As you noticed, they share all the same signals.

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Well, that’s unfortunate. I guess this pad is just wasted space as long as the uSD socket is in use.

so if understand the docs correctly, if I wanted to use a W25N01, I need to pull down SPINOR_NAND_TX (pulled down in duo_iob_v11.pdf, but left floating per duo-datasheet-v1.2.pdf).

now, since the cv1800 is the SPI master, I assume the TX in SPINOR_NAND_TX means MOSI; therefore, soldering a 4k7 resistor between pin 25 (GPIOA22/NAND_MOSI) and pin 23 (GND) should pull that line low, and thus enable NAND boot.

anyone tried that? I’m particularly interested if there’s any reason why this wouldn’t work

Hi @mionica, yes the 5th pin is MOSI, and using 4k7 to GND allows successful boot with W25N01.

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