Skip to main content
Dany1
Dany1
Associate
April 6, 2021
Solved

Can someone advice a psram for STM32F479 LQFP100 ?

  • April 6, 2021
  • 3 replies
  • 1662 views

Dear Community,

can someone advice a min 8Mbit psram for the STM32F479?

I only find some who has address pins up to A20 but the uc has only up to 16 or did I missunterstand something?

best regards

This topic has been closed for replies.
Best answer by M.Hajji

Hello @Dany​,

I suggest to look at AN4861, Table 20 "Example of graphic implantations with STM32 in different hardware configurations", for 400x600 I think at least you need LQFP144 package and with LQFP100 you should aim for low end display configuration.

For the PSRAM with STM32F479 LQFP100, you need a ADMUX Pseudo SRAM (support a multiplexed address/data bus) for example AS1C4M16PL-70BIN but with the STM32F479 LQFP100 you don't have the upper address signals available (A[21:16]), so you only have 16 address signals to work with.

To calculate the size of the memory knowing number of address lines and data width you have the formula:

Size = (2^(number of address lines)) * data width

For example, the one you attached have 19 address line and 16bit data width so:

(2^19) * 16bit = 512K * 16 = 8Mbit

and in the case of F479 LQFP100 you have:

(2^16) * 16bit = 64K * 16 = 1Mbit

Hope this help.

Regards,

Mahmoud.

3 replies

Imen.D
ST Technical Moderator
April 6, 2021

Hello @Dany​ ,

Which package are you using ?

It depends on the package that you are used.

You can check the PSRAM configuration and address max with STM32CubeMX.

For example, with LQFP100 package : Max 16 bits for Muxed PSRAM.

0693W000008ynGAQAY.jpgYou can refer to the Table 10. STM32F479xx pin and ball definitions in the STM32F479xx datasheet to check the PSRAM address pins.

0693W000008ymw5QAA.jpgImen

In order to give better visibility on the answered topics, please click on 'Best answer' on the reply which solved your issue or answered your question. Thanks
Dany1
Dany1Author
Associate
April 7, 2021

Sorry - I have to use the STM32F479 in LQFP100 package but somehow I can't find any PSRAM with up 8Mbit+ which can be used.. or I missunderstand how it should work.

Hopefully you can help me to get in the rigth direction.

EDIT: Am I right that if I use this RAM I'm only able to use 128 kbyte by leaving A16-A18 unconnected / gnd?

So it looks like its not possible to drive 400 x 600 display with that package?

Thanks

M.Hajji
M.HajjiBest answer
Visitor II
April 12, 2021

Hello @Dany​,

I suggest to look at AN4861, Table 20 "Example of graphic implantations with STM32 in different hardware configurations", for 400x600 I think at least you need LQFP144 package and with LQFP100 you should aim for low end display configuration.

For the PSRAM with STM32F479 LQFP100, you need a ADMUX Pseudo SRAM (support a multiplexed address/data bus) for example AS1C4M16PL-70BIN but with the STM32F479 LQFP100 you don't have the upper address signals available (A[21:16]), so you only have 16 address signals to work with.

To calculate the size of the memory knowing number of address lines and data width you have the formula:

Size = (2^(number of address lines)) * data width

For example, the one you attached have 19 address line and 16bit data width so:

(2^19) * 16bit = 512K * 16 = 8Mbit

and in the case of F479 LQFP100 you have:

(2^16) * 16bit = 64K * 16 = 1Mbit

Hope this help.

Regards,

Mahmoud.

Terms & ConditionsAccessibility statement