Microchip SD/MMC SPI conflict

Hi,

I am trying to use the Microchip MDDFS library to write and read from a SD Card.

At first I was just using the sd card in the SPI bus but then I inserted a RTC in the SPI bus with no problem. Everything worked perfectly.

At this moment I am trying to introduce a flash memory to the SPI bus.

First I tried with the memory and the RTC and the system worked with no problems but when I tried inserted the SD card in the SPI bus the flash memory started to develop some problems.

Most of the time I am unable to access the memory and when the system can access the memory the stored data is corrupted.

It seems to be some kind of conflict between the flash memory and the sd card. Probably because of Microchip library.

I am using the PIC18F87K22.

Did anyone had the same problem? Do you have any ideia how to fix it?

clem57 over 9 years ago

Check the chip select logic and match up with the correct hardware lines. When you have many SPI devices, the code to arbitrate gets dicey (hard to manage).
Clem
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eduardo.goncalves over 9 years ago in reply to clem57

Hi Clem,
All the lines are corrected and each chip select has his own pull up resistor.

I am not sure if the problem is related with the Microchip library of even with the SD Card socket.
The only problem is when I join the flash memory and the sd card.
I tried to change the chip select pins but the result is the same. I cannot use the other SPI bus. I need to use all the devices in the same SPI bus.

Eduardo
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