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JKim.2
Associate III
April 14, 2025
Question

how to set OCTOSPI1 of STM32L4P5G-DK as 1.8V instead of 3.3V?

  • April 14, 2025
  • 4 replies
  • 1198 views

Hello,

 

Testing 3.3V Octo-SPI PSRAM is fine on the STM32L4P5G-DK board. I'd like to test another 1.8V Octo-SPI PSRAM now. The solder bridge options SB17/SB18 for PSRAM and SB13/SB14 for MCU are modified for the purpose. However, a certain DQ bit is still failing. What else do I have to configure accordingly?

 

Thanks.

4 replies

Mike_ST
Technical Moderator
April 14, 2025

Hello,

>> The solder bridge options SB17/SB18 for PSRAM and SB13/SB14 for MCU are modified for the purpose. What else do I have to configure accordingly?

That should be it, unless you're connecting a chip that requires different connections than the ones available on the STM32L4P5G-DK.

>> However, a certain DQ bit is still failing.

You means only one data line is failing ? Could it be a bad solder ?

 

 

 

 

JKim.2
JKim.2Author
Associate III
April 15, 2025

Hello @Mike_ST ,

 

The 1.8V Octo-SPI PSRAM has the exact same 24-ball configuration as the original 3.3V Octo-SPI PSRAM. 

only the bit17 in 32bits is failing. other 31bits are fine. The OCTOSPI1 speed was set as 60MHz. (SYSCLK 120MHz, prescaler 2) as AN5050 introduced. Do I still need to configure something in the .ioc file?

 

Thanks.

Mike_ST
Technical Moderator
April 15, 2025

Hello,

Hard to tell, maybe timing related.

Please have a look at the following application note:

AN5050 

EZHON.1
ST Employee
April 16, 2025

what's do you mean to test 1.8V Octo SPI device?

for my understanding, most of the Octo SPI only support 3.3V or 1.8V range. if you want to test them, I think you will solder a new Octo SPI memory which support 1.8V only?

 

JKim.2
JKim.2Author
Associate III
April 16, 2025

Hello @EZHON.1 ,

 

Yes. the device codes of Octo-SPI PSRAM are separated for 1.8V and 3.3V Vdd. I replaced the existing 3.3V PSRAM by 1.8V PSRAM. Do you think I need to configure another thing except changing the two solder bridge options?

 

Thanks.

EZHON.1
ST Employee
April 16, 2025

Personally, it should be OK. you have selected 1.8V for OctoSPI and MCU IOs.

could you check the soldering firstly?

 

EZHON.1
ST Employee
April 23, 2025

Hello, @JKim.2 

OctoSPI is 8 bits data. If you can get the first 2x8 bits without issue, it's no Hardward issue. do you test "0" and "1" in bit 17 is the same issue? maybe related to FW configuration?

 

JKim.2
JKim.2Author
Associate III
April 23, 2025

Hello @EZHON.1 ,

 

As I mentioned at the beginning, 3V PSRAM has no issue. Then the FW configuration is fine I guess. Do I need to change any FW configuration for 1.8V?

The expected '2' turned to '0' in the failure log.

              FAILURE: mem_addr = 0x903408c4 antipat = fff2fdcd output = fff0fdcd

              FAILURE: mem_addr = 0x903408c8 antipat = fff2fdcc output = fff0fdcc

Thanks.

EZHON.1
ST Employee
April 23, 2025

It's strange. the bit1 of the 8 bits date is right for bit 1, bit 9 and bit 25, only fails at bit 7. can you write others liking: "fff2fdcd", "55AA55AA" or "AA55AA55"?