i.MX Processors中的主题 Re: iMX117H SDRAM Too Slow

iMX117H SDRAM Too Slow

MFurkan — Mon, 27 Nov 2023 14:15:48 GMT

Hi,

I have a custom board with NXP iMX1176 chip, using the following code ;

#define buffersize (1U*1024U*1024U) volatile uint32_t test_buf[buffersize]; bool x = false; while (1) { for (uint32_t i = 0; i < buffersize; i++) { test_buf[i] = i; } for (uint32_t i = 0; i < buffersize; i++) { if (test_buf[i] != i) { while (1); } } GPIO_PinWrite(BOARD_Audio_RST_GPIO, BOARD_Audio_RST_PIN, x); x = !x; }

Pin toggle is 800ms in my custom board;

https://www.digikey.com/en/products/detail/etron-technology-inc/EM63A165BM-5IH/10321539

This is the SDRAM which i am using.

I tested the same function in this evaluation kit ; https://www.nxp.com/design/designs/nxp-edgeready-smart-hmi-solution-based-on-i-mx-rt117h-with-ml-vision-voice-and-graphical-ui:SLN-TLHMI-IOT-RD

and getting 60ms pin toggle time ,

i have same dcd.c and dcd.h files with eval. board,

for both custom board and eval board SDRAM clocks are same = 200MHz

you can find my clock configuratios on the below picture;

What is the problem? Why my custom board is too slower than eval kit? More thanks for help fron now on.

Re: iMX117H SDRAM Too Slow

jingpan — Wed, 29 Nov 2023 08:28:28 GMT

Hi @MFurkan ,

Where is this test code? You can put this code in ITCM. This can speed up read/write speed.

This is our test report.

Write is far more faster than read. It's because write operation is pipelined, but read operation must wait till SDRAM feedback.

Regards,

Jing

Re: iMX117H SDRAM Too Slow

MFurkan — Wed, 29 Nov 2023 08:41:08 GMT

Hello @jingpan

The buffer is located in BOARD_SDRAM section as shown below;

I would like to run LVGL so the frame buffer should be located here. The capacity of ITCM is not sufficient. I have made the same test on the eval kit speed is 12-13 time better. What could be problem for my custom board?

Re: iMX117H SDRAM Too Slow

jingpan — Wed, 29 Nov 2023 09:13:01 GMT

Hi @MFurkan ,

What's the difference in hardware and software?

Regards,

Jing

Re: iMX117H SDRAM Too Slow

MFurkan — Wed, 29 Nov 2023 13:26:55 GMT

Hi again @jingpan ,

In our custom boards we have following components;

SDRAM @200MHz;SDRAM which we are using in the custom board

MCU : MIMXRT117HCVM8A @768 MHz

For evaluation kit you can refer ; NXP Eval Kit

Software is almost same with eval kit , so what is the problem with our custom board?

Re: iMX117H SDRAM Too Slow

jingpan — Thu, 30 Nov 2023 02:39:08 GMT

Hi @MFurkan ,

Maybe the SDRAM is not configured properly. Can you use oscilloscope to measure the SDRAM signal?

Regards,

Jing

Re: iMX117H SDRAM Too Slow

MFurkan — Thu, 30 Nov 2023 08:16:28 GMT

Hi @jingpan

I measured both custom board and eval kit SDRAMs with oscilloscope you can see the results on the below;

194MHz custom board

200MHz eval kit

Note:My oscilloscope is capable to measure 100MHz signals.

Do you have any suggestion to measure any other signal(s)?

Re: iMX117H SDRAM Too Slow

jingpan — Thu, 30 Nov 2023 08:50:57 GMT

Hi @MFurkan ,

Is this SEMC_CLK? What's the DQS signal look like? It represent read sequence and speed.

Regards,

Jing

Re: iMX117H SDRAM Too Slow

MFurkan — Thu, 30 Nov 2023 09:56:49 GMT

Hello again @jingpan

This is our custom boards DQS signal look like shown below;

Best Regards,

Furkan

Re: iMX117H SDRAM Too Slow

jingpan — Thu, 30 Nov 2023 10:22:54 GMT

Hi @MFurkan ,

Please enlarge the time window, I need more signal in a screen. Please also add SEMC_CLK signal to another channel.

The interleave of the two DQS is 200ns. So the max speed is 5M word or 20M byte. Please refer to figure 29-12 in reference manual.

Regards,

Jing

Re: iMX117H SDRAM Too Slow

MFurkan — Thu, 30 Nov 2023 14:19:01 GMT

hi @jingpan

this is the signals which i catched

regards,

Furkan

Re: iMX117H SDRAM Too Slow

jingpan — Fri, 01 Dec 2023 07:16:00 GMT

Hi @MFurkan ,

It looks like there is 4 continue DQS in a read sequence. As I analyze in last reply, it is about 20*4=80M, not too bad. If the burst length is 8, it can be even better.

Maybe there is other problem in your code?

Regards,

Jing