Strange problems with SD card

[ParaPashka]

Hello.
I have connected SD cardreader to a esp-wroom-32 using VSPI.
This is my simple test code:

Code: Select all

import machine, uos
uos.mount (machine.SDCard(slot = 2), "/sd")

print(uos.listdir('/'))
file = open('/sd/test.txt', 'w')
file.close()

for i in range(10):
    file = open('/sd/test.txt', 'a')
    file.write('\nnext data'+str(i))
    file.close()
    
file = open('/sd/test.txt', 'r')
print(file.read())
file.close()

The connection is very unstable.
Without any changes to hardware or software, just restarting the programm,
sometimes i get OSError: 16,
sometimes OSError: [Errno 19] ENODEV,
sometimes the SD is mounted. But then i get strange results when reading and writing to file. Here it is:

['sd', 'SDCard_test.py', 'boot.py', 'log.txt', 'sdcard.py', 'test.txt']

next data0
next data2
next data3
next data4
next data5
next data6
next data7
next da48
next data9
>>> %Run -c $EDITOR_CONTENT
['sd', 'SDCard_test.py', 'boot.py', 'log.txt', 'sdcard.py', 'test.txt']

next data0
next data2
next data3
next data4
next data5
next data6
next data7
next dat`8
next data9
>>> %Run -c $EDITOR_CONTENT
['sd', 'SDCard_test.py', 'boot.py', 'log.txt', 'sdcard.py', 'test.txt']

next data0
next data2
next data3
next data4
next data5
next data6
next data7
next da4!8
next data9
>>> %Run -c $EDITOR_CONTENT
['sd', 'SDCard_test.py', 'boot.py', 'log.txt', 'sdcard.py', 'test.txt']

next data0
next data2
next data3
next data4
next data5
next data6
next data7
next da0!8
next data9

Where is the "next data1"?
Why i always get a mistake in "next data8"?
What do I need to do to get stble connection to SD card?

[pythoncoder]

Could there be electrical issues? The interface runs at 40MHz so lead lengths need to be kept very short. Another option might be to try different SD cards. There have been issues with certain types of card.