Memory Usage in i.MX8ULP

[hwyou0212]

I found that use the contents of PSRAM  for " always on display"at "RTD domain active with LPAV"  part in AN13591.

Please, let me know if this PSRAM is the RAM connected to M33.

And, I understand that DDR memory can be connected to LPAV.

I would like to know what this DDR is used for and whether it is absolutely necessary.

[Zhiming_Liu]

Hi @hwyou0212 

The M33 can access pSRAM via FlexSPI1 for HiFi4 code and data. The multicore communication needs DDR.

Best Regards
Zhiming

[hwyou0212]

Hi,

Thank you for your quick response.

I couldn't understand your reply well.

And, I would like to organize my questions and inquire as follows.

1. I would like to try to execute the always on display function at Real Time Domain in i.MX8ULP for saving battery power.

In this case, could I transfer contents of RAM connected with M33 to Flex Domain,  then display in screen through  MIPI DSI.?

2. In case of displaying contents through Flex Domain, should need any DDR Memory connected with Flex Domain? 

3. What is the usage purpose of DDR being able to connect with Flex Domain as option? 

BR,

Hyunwoo You

[Zhiming_Liu]

Hi @hwyou0212 

For Always on Display demo, you can refer 5.8.6 Always-ON display, 1 fps refresh rate in this AN and attachments.

Zhiming_Liu_0-1721789280516.png

https://www.nxp.com/products/processors-and-microcontrollers/arm-processors/i-mx-applications-proces...

The frame buffer is allocated in pSRAM through FlexSPI and the display controller fetches display content from pSRAM. 

The DDR is necessary as the A core would run on it and it also act as shared memory.

Best Regards
Zhiming

[hwyou0212]

Dear Zhiming,

Please, check that I understood  about your response correctly.

1. To allocate Frame Buffer for Always-On function need a pSRAM memory connected with RTD.

2. To execute codes for A core need a DDR memory connected with APD.

BR,

Hyunwoo You

[hwyou0212]

Hi, Zhiming,

I would know which of memory use for allocating a frame buffer as follows: 

hwyou0212_0-1722305893851.png

For example, in LPAV or RTD(M33).

BR,

Hyunwoo You