Christoph Gottschlih

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10 years, 11 months ago.

SD Card using all Pins

Hi,

i actually use SPI to communicate with an ifstream and an ofstream with my SD_Card. But that is not fast enough. A friend told me, I can use the SD-Card as memory without the FAT-FileSystem and use all Pins. (4 Digital Inputs). Does anyone know how to? Or has any literature for me or examples how it works?

Thanks for help

Chris

2 Answers

ceri clatworthy
10 years, 11 months ago.

If you want FAST data In/Out, then consider a separate memory chip, Farnell (etc) have 10's of thousands !!

this way you can loose file-system, but be warned, the Port out (Fast Port Out) and the subsequent chip select, write, and addressing, might not give you an advantage !

I belive the 4-bit mode for SD is proprietary, and not Open Source (yet)

I would look at a 16 bit serial FLASH SPI device, I do recollect Microchip claim to be the fastest & biggest ?

Hope this was some use.

Ceri

EDIT

Microchip: SST25VF032B-80-4I-S2AF

32 MBit = 4K Byte's (8 Bit)

Farnell #1829955 £1.80

Accepted Answer

The problem is, i need more Flash. I need 15 Mbyte. Thats why i choose the SD Card. I need to write and read 16 Bit in 0,5 ms ...

posted by Christoph Gottschlih 15 Apr 2014
Peter Drescher
10 years, 11 months ago.

There are some mbed boards with a embedded SD controller - LPC4088, ST Nucleo L152RE, ST Nucleo F401RE ... ?, but only the LPC4088 has implemented a driver today. Because of the bit banging on the clock line you will not win so much speed. If you need a faster SD card access with the mbed lib today, you have to switch to the LPC4088 board. It looks like the driver is using dma. Has someone test the speed of this implementation ?