This is [another] swift implementation of interfacing to the affectionatly known Cat-Printers.
The printers have a greyscale/hd mode of 4bpp 0x02, but this is tricky to get working.
After using apple's PacketLogger.app (From XCode additional tools) I could sniff the
BLE packets for the truly awful "official" app Fun Print.
- The print command packet MUST end with
0x00instead of0xfffor 4bpp mode.0xffworks fine for 1bpp - Max MTU is 182 bytes
- Checksum seems irrelevent?