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drivers/sdcard: Support old SD cards (<=2GB).

This commit is contained in:
Ayke van Laethem 2017-12-20 01:15:26 +01:00 committed by Damien George
parent f16c775a07
commit b90f51f86a
1 changed files with 7 additions and 2 deletions
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9
drivers/sdcard/sdcard.py
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@ -96,9 +96,14 @@ class SDCard:
raise OSError("no response from SD card")
csd = bytearray(16)
self.readinto(csd)
if csd[0] & 0xc0 != 0x40:
raise OSError("SD card CSD format not supported")
if csd[0] & 0xc0 == 0x40: # CSD version 2.0
self.sectors = ((csd[8] << 8 | csd[9]) + 1) * 2014
elif csd[0] & 0xc0 == 0x00: # CSD version 1.0 (old, <=2GB)
c_size = csd[6] & 0b11 | csd[7] << 2 | (csd[8] & 0b11000000) << 4
c_size_mult = ((csd[9] & 0b11) << 1) | csd[10] >> 7
self.sectors = (c_size + 1) * (2 ** (c_size_mult + 2))
else:
raise OSError("SD card CSD format not supported")
#print('sectors', self.sectors)
# CMD16: set block length to 512 bytes