MSP432P401R: MSP432 directly addressable external SRAM

Robert Cachro

Part Number: MSP432P401R

Hi,

We currently need to add some extra memory to our application using the MSP432P401R. Ideally we would prefer directly addressable external SRAM using the MSP432P401R which may not be possible. However, I came upon a posting (https://e2e.ti.com/support/microcontrollers/msp430/f/166/t/685531) which stated this was possible to do using the MSP432P4111. I spoke with a TI field applications engineer today and we found no mention of any native support for parallel SRAM in the datasheet.

If this is indeed possible, can you please provide additional information or point to a datasheet / whitepaper / code showing how this can be done?

Otherwise if TI has a better solution for directly addressable external memory using MSP432P401R, besides implementing a driver to communicate with external memory, we would appreciate your input.

Best,

Robert

over 6 years ago

0 Keith Barkley over 6 years ago

Guru 41995 points

You did not read my post correctly. You cannot add external memory to the P4111. However, the P4111 has 2MB of Flash and 256Kb of SRAM compared to the P401R's 256K of Flash and 64K of RAM.

How much more memory do you need?

0 Robert Cachro over 6 years ago in reply to Keith Barkley

Intellectual 845 points

I see now. We now have provisions for 4MB external memory but only require about 2MB. However, we are limited to the 64pin P401Rs package size. The 100pin P4111 is too large for our PCB.

0 Sai Reddy over 6 years ago in reply to Robert Cachro

TI__Mastermind 22580 points

Hello Robert,

Robert Cachro said:
However, we are limited to the 64pin P401Rs package size. The 100pin P4111 is too large for our PCB.

Can you use the MSP432P4011 device? It has the bigger memory but the same 64pin VQFN package as MSP432P401R. See screenshot below. The power consumption is slightly higher for the MSP432P4011 when compared to MSP432P401R. Also some of the peripherals are less on MSP432P4011 when compared with MSP432P401R. Please review the differences carefully!

Thanks,

Sai

0 Robert Cachro over 6 years ago in reply to Sai Reddy

Intellectual 845 points

We will review. Thank you.

0 Keith Barkley over 6 years ago in reply to Robert Cachro

Guru 41995 points

Is that 2MB of Flash or 2 MB of SRAM?

0 Robert Cachro over 6 years ago in reply to Keith Barkley

Intellectual 845 points

SRAM

0 Keith Barkley over 6 years ago in reply to Robert Cachro

Guru 41995 points

Then the higher memory MSP432's won't work, They only have 256K of SRAM.

0 Robert Cachro over 6 years ago in reply to Keith Barkley

Intellectual 845 points

Unfortunately yes, we’ll have to go with non-directly addressable SRAM.. add a SPI layer for communication.

0 Keith Barkley over 6 years ago in reply to Robert Cachro

Guru 41995 points

If you have enough GPIO's, you could use directly addressable RAM. You could throw in a high order bit latch, to save on IO's at the expense of time.

0 Robert Cachro over 6 years ago in reply to Keith Barkley

Intellectual 845 points

We currently are limited by GPIOs but nevertheless thank you for the tip.

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MSP432P401R: MSP432 directly addressable external SRAM