AM3357: support serial MRAM for flash interface?

Hello Brad Caldwell

Thank you for the query.

Brad Caldwell said:

Do you know it the TI AM3357BZCZA80 CPU can support serial MRAM for flash interface?

Can you please elaborate your query including what you meant by flash interface.

Is there a part number that you could share.

Regards,

Sreenivasa

Here's a link to the datasheet

https://www.avalanche-technology.com/wp-content/uploads/1G-8Gb-Dual-QSPI-Space-Grade-Serial-E-01_10_2023.pdf

Want to boot from it, I assume this would need to be SPI0 (CS0) SPI EEPROM boot mode with single data line

Hello Brad Caldwell

Thank you for sharing.

On a quick look i am assuming that the device might not be supported by the Am335x SPI bpoot 

AM335x 

26.1.8.6 SPI

26.1.8.6.1 Features

• Supports 12-MHz clock (50% duty cycle).

• Supports only SPI Mode 3 (clock polarity = 1, clock phase = 1).

• Supports only 24-bit addressable EEPROMs.

• Supports only 4-pin SPI mode (CS, CLK, Serial Input, Serial Output).

• The boot devices must be connected to chip select 0 and must support the read command (03h).

• The boot image is copied into internal memory and then executed.

Device 

Memory Map Table 12: Memory Map

I need to consult the expert internally if you further need inputs. Let mw know your thoughts.

Regards,

Sreenivasa

I think your right. I saw the MRAM device expects a 32-bit address field for the read commands. Our ROM code only sends a 24-bit address field. That right there makes it incompatible for boot. 

For normal runtime accesses, I don't see any issues, 4-wire SPI mode 3. With proper driver software, they should be able to create read/write commands. They would only be able to access one chip select at a time even though the MRAM is a dual die device. They would also have to manage the block protection signals using GPIOs.