Epson HX-20 - Manual (Page 70)

As shown in Figure 9-1, the main microprocessor accesses read-
only and read-write memory, and controls the keyboard, LCD
display, and clock. The slave microprocessor controls the micro-
printer, speaker, and external cassette. The cartridge interface has
ports for both the main and slave microprocessors.
HX-20
ROM
SOCKET
8 K B
6301
MAIN CPU
BARCODE READER
INTERFACE
CARTRIDGE
INTERFACE
6301
SLAVE CPU
CASSETTE TAPE
INTERFACE
POWER
SUPPLY
66