Datasheet

Chapter 2 — Theory of Operation
14 PB42 Portable Receipt Printer Service Manual
Memory reads and writes have the following format: Read/write op-code,
lower 8 bits of address, data. For multiple byte transfers, the address is
automatically incremented. If the address reaches 0x1FF, the next address is
0x000.
Memory Write
Memory Read
Input/Output Shift Registers
Due to a shortage of GPIO pins on U1, input and output shift registers are
connected to the SPI.