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Topic: 3.3V SD card reader issues (Read 336 times) previous topic - next topic

syphex

Ok, thanks. Does it need to set it to high to finish the writing operation? Or is it just a convention to set the device high after talking to it? Why is it writing jumbled characters and files to the SD?

Juraj

#16
Nov 09, 2018, 01:01 pm Last Edit: Nov 09, 2018, 01:05 pm by Juraj
Ok, thanks. Does it need to set it to high to finish the writing operation? Or is it just a convention to set the device high after talking to it? Why is it writing jumbled characters and files to the SD?
it is only slave select. only the slave device with CS LOW should listen and response

clear the card in a computer and make new test. still MOSI has 5 V signal to 3.3 V card
You can't write an Arduino sketch if you didn't learn programming. Not the language, but the concepts of programming - algorithms and data types.

nathan_ngu

I gotchu fam.

The SD Card MUST be formatted to FAT 16 (FAT), otherwise the data size will be incorrect.

The Kingston MicroSD card only formats to FAT 32. You need one that formats to FAT 16

Usually the only types of SD cards that work are 2-4gb.

I found one that works on an old camera.

Juraj

I gotchu fam.

The SD Card MUST be formatted to FAT 16 (FAT), otherwise the data size will be incorrect.

The Kingston MicroSD card only formats to FAT 32. You need one that formats to FAT 16

Usually the only types of SD cards that work are 2-4gb.

I found one that works on an old camera.
not true. SD library works with FAT32 and with large cards
You can't write an Arduino sketch if you didn't learn programming. Not the language, but the concepts of programming - algorithms and data types.

syphex

#19
Nov 13, 2018, 09:27 pm Last Edit: Nov 13, 2018, 09:33 pm by syphex
I suspect the card reader simply does not work with 5v TTL unless you change the surface-mount resistors. I don't understand why because the thresholds for 3.3v and 5v TTL seem compatible.

I tried to use a 10k and 4k7 resistive divider for 3.4v output for the CS pin, but then it doesn't even initialize anymore.

Also isn't 64 blocks per cluster too large? I only need to write 5-6 csv values at a time.

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