i.MXRT117x FlexSPI and APMemory Xccela PSRAM with 16-bit bus

[eamonnheffernan]

Hi,

I’d like to connect an AP Memory 16-bit Xccela PSRAM (APS256XXN-OBRx) to an i.MXRT117x using a 16-bit FLEXSPI2 configuration.

AP datasheet: https://www.mouser.ie/datasheet/2/1127/APM_PSRAM_OPI_Xccela_APS256XXN_OBRx_v1_0_PKG-1954780.pdf

Here’s my proposed wiring scheme:

FLEXSPI2_A_DATA0-7 to PSRAM_DQ0-7
FLEXSPI2_B_DATA0-7 to PSRAM_DQ8-15
FLEXSPI2_A_DQS to PSRAM_DQS/DM0
FLEXSPI2_B_DQS to PSRAM_DQS/DM1
FLEXSPI2_A_SCLK to PSRAM_CLK
FLEXSPI2_A_SS0_B to PSRAM_CE#

1. Does that look right?
2. Has anyone tried this PSRAM device in 16-bit mode with an 117x? Any gotchas?
3. Does this configuration get anyway close to 800MB/s for a linear read?

Thanks - Eamonn

[Alex-APMemory]

Hi Eamonn, 

fyi, this device can also be used as x8 only, and at 200MHz (400MB/s). When their application allows it, some customers are using 2 OPI RAM independently on each of the FlexSPi memory controller to double the bandwith (equivalent to x16 performance).

Alex

PS: IoT RAM are covering densities from 16Mb up to 512Mb (QSPI from 16Mb up to 128Mb & OPI from 64Mb up to 512Mb, with 256Mb & 512Mb supporting x8 &x16 mode)

[eamonnheffernan]

Omar, thanks so much for your replay.

I'm delighted to hear that this configuration is viable. We are designing a pcb at the moment and it is reassuring to know that it will work.

I reread the datasheet and indeed the FlexSPI maxes out at 166MHz, so peak potential is 166 x 2 (16b) x 2 (DDR) = 664MB/s. I've been testing SDRAM on the 1170-EVK and we get a max of 333MB/s. In a previous iteration of this board based on the i.MXRT1050, we compared Hyperflash and SDRAM and we found Hyperflash to be 2x the read performance of SDRAM. I'm hoping we will see similar gains with HyperRAM vs SDRAM. A lot less wires to route as well.

Thanks again Omar - Eamonn

[Omar_Anguiano · Accepted solution]

Hello

Hope you are well.
I will gladly answer your questions:
1. The wiring scheme looks good.
2. I do not found someone that used this memory in 16bits mode however, I believe that this application note might be useful: https://www.nxp.com/docs/en/application-note/AN13028.pdf
3. No, since the max support for FlexSPI is 166MHz.

If you have more questions do not hesitate to ask me.
Best regards,
Omar

[eamonnheffernan]

Bump! Anyone? Can 117x read a 16-bit PSRAM device?

[Alex-APMemory]

i.MXRT117x or in general FlexSPi interface is not supporting the x16 mode of APMemory IoT RAM, but all other options OPI (11pins - 400MB/s)), QSPI DDR (7pins - 166MB/s) or QSPI SDR (6pins - 72MB/s). .

The HPI (x16) option for IoT RAM (APS256XXN-OBR-..., APS512XXN-OBG...) is supported by all SoC having  xSPI memory controller (currently I.MX 8 ULP, in future others including RT series...)

Alex

[eamonnheffernan]

Alex, thank you very much for letting me know. I'm disappointed that the 117x won't work in 16-bit mode with the AP Memory Xccela PSRAM. But at least now I know of the problem before we print a board.

Thanks again for the notice. Much appreciated - Eamonn