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Half working external SDRAM

Question asked by Chico Boot on Sep 25, 2018
Latest reply on Sep 28, 2018 by Chico Boot

Hello,

I'm having some problems with the ISSI 42-45S16100H external SDRAM. The microcontroller that i'm using is the LPC54607.

 

The SDRAM contains 2 memory banks, but it seems that i can only write and read properly to bank 0. If I write, for example, 2048 bytes to bank 0 and read and verify the data back, the data is OK. If I write 2048 bytes to bank 1, the data that I read back all have the same value: 0xFFFFFFFF. BUT if I write 128 bytes to bank 1 and read and verify the data back, the data is OK. If I write 2048 bytes to bank 1 in blocks of 128 bytes, and verify the data after every block, the data is OK. But after writing the 2048 bytes, when verifying the 2048 bytes, the data all has the same value 0xFFFFFFFF.

 

So i'm able to write and read to bank 0, but with bank 1 i'm having some problems.

 

I've initialised the SDRAM and the EMC peripheral with the NXP EMC driver functions. The clock supplied to the SDRAM is configured to 48 MHz. The initialise procedure of the SDRAM and some tests are provided in the file attached. I've also provided the datasheet of the SDRAM.

 

Can somebody help me?

 

Best regards,

Chico

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