sd card shows up empty
On my MK3 with older, and just-updated firmware, all SDcards show up empty, even when freshly formatted with FAT32. Symptom is similar to:
1)
Can prusa provide an small image that can be linearly/sequentially written to the SDcard (i.e. RPI disk imaging tool), containing the right partitiontable, filesystem headers, and sample g-code files, that leaved the SDcard blockdevice in a state that should be able to be read by any MK3 firmware ?
2) more technical questions
Where do I find the firmware source ? Is the SDcard accessed in SPI mode ? What if signals CMD and DAT0 is ok, but DAT1..DAT3 are degraded? Are MMC commands attempted ? What sequence of blocks are read ? Are there any flags that can confuse the display of the root directory ? Are there limitation on how the 'System Volume Information' directory is organized ? I do not have a logic analyser / easy way to probe this issue right now - and I undestood that the firmware is already very tight in footprint...
Best Answer by cmpxchg:
I think I found the problem. I disassembled the control PCB, and looked into the slot with a microscope, focussing in the depth of the SD card reader slot.
There was a small blue fragment 1x1x1 mm stuck in the slot. I lifted up the metal lever and the part dropped out of the slot.
After a few attempts, an SD card could be detected, and also being read.
RE: sd card shows up empty
I think I found the problem. I disassembled the control PCB, and looked into the slot with a microscope, focussing in the depth of the SD card reader slot.
There was a small blue fragment 1x1x1 mm stuck in the slot. I lifted up the metal lever and the part dropped out of the slot.
After a few attempts, an SD card could be detected, and also being read.
RE: sd card shows up empty
It is intermittent - inserting SDcard and turning printer off and on again seems to work - I guess the card insertion/powerrail of card is not perfect yet.