AM2631: Is the size of the application limited by the amount of internal RAM?

Javier Rico

Part Number: AM2631
Other Parts Discussed in Thread: AM2634

Given that AM2631 does not support XIP (eXecution In Place), is it fair to assume that the complete SBL and Application (from Flash through QSPI) are transferred to internal RAM and thus the amount of internal RAM is the hard limit for both (considering code and data)?

We are evaluating the need to have external RAM connected through GPMC. Similar legacy systems use approximately 1MB for Bootloader + 2MB for application for a total of 3MB of Flash, and 2MB of RAM.

Regards,

Javier

over 1 year ago

+1 Aakash Kedia over 1 year ago

TI__Mastermind 26145 points

Hi Javier Rico,

Yes the Application is limited by the size of internal RAM i.e. 2MB of SRAM and 256KB of TCM memory.

Your SBL or Bootloader will only require the RAM during the boot-time. You can "reclaim the memory" back after the application execution is started. You can plan to develop an application linker with "no load" sections like stack and bss from the same memory as SBL execution which will be used by Application after SBL resets.

Best Regards,
Aakash

0 Javier Rico over 1 year ago in reply to Aakash Kedia

Prodigy 70 points

Thanks for the reply Aakash,

As the legacy systems had their own bootloader to allow reflashing the application through a serial port, for the new system we would like to use SBL+reflashing capability and application, thus will not be able to reclaim the memory.

Is RAM through GPMC the only option to increase the memory?

Regards,

Javier

0 Aakash Kedia over 1 year ago in reply to Javier Rico

TI__Mastermind 26145 points

Hi Javier Rico,

In my opinion you should go through the errata sheet - https://www.ti.com/lit/er/sprz488d/sprz488d.pdf

If you are unaffected by this errata, then you should consider GPMC with this device.

I hope this helps.

Best Regards,
Aakash

0 Javier Rico over 1 year ago in reply to Aakash Kedia

Prodigy 70 points

Hi Aakash,

I am taking a look at the GPMC PSRAM code in the SDK 09.01.00, and in there the read access to GPMC appears as 16-bit in function Psram_gpmcRead:

volatile uint16_t *pSrc = (volatile uint16_t *)(offset+baseAddress);

volatile uint16_t *pDst = (volatile uint16_t *)buf;

I don't have a external RAM memory to test this code, but is it working or should be changed to 32-bit access?

Regards,

Javier

0 Aakash Kedia over 1 year ago in reply to Javier Rico

TI__Mastermind 26145 points

Hi Javier,

Let me connect you to the expert here.

Best Regards,
Aakash

0 QJ Wang over 1 year ago in reply to Aakash Kedia

TI__Guru**** 196346 points

Hi Javier,

AM2634 doesn't support XIP. The code can't execute from the external psRAM (NOR flash-like memory).

0 Javier Rico over 1 year ago in reply to QJ Wang

Prodigy 70 points

Hi QJ,

Should the following lines, from the SDK 09.01.00 GPMC PSRAM example, be changed to uint32_t when reading (Psram_gpmcRead)? This, due to the errata i2313

volatile uint16_t *pSrc = (volatile uint16_t *)(offset+baseAddress);

volatile uint16_t *pDst = (volatile uint16_t *)buf;

Regards,

Javier

+1 QJ Wang over 1 year ago in reply to Javier Rico

TI__Guru**** 196346 points

The errata is for sub-32 bit read from NAND flash. This doesn't affect sub-32 bit reading from psRAM.

It would be fine to use uint32_t.

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AM2631: Is the size of the application limited by the amount of internal RAM?