Slave Cpu 6303 - Epson PX-8 Technical Manual

REV.-A
7.2 Slave CPU 6303
6303 is a 6800-series, 8-bit, C-MOS CPU. It incorporates a 4kB masked ROM which contains
programs for controlling the microcassette tape drive, ROM capsule, V-RAM, LCD display unit,
serial interface, and speaker. A mode six (Multiplexer Partial/Decode) is selected for the control
operations. Stand-by and sleep modes, unique to 6303, are not used.
RES
ROM
IRQ
4K
NMI
E
EXTAL RAM
XTAL
128
Fig. 7-26303 Slave CPU Functional Block Diagram
Table 7-2
This computer uses a crystal oscillator for a
2.4576 MHz clock signal. The slave CPU oper-
ates with the 614.4 kHz system clock signal
which is internally quartered from the primary
frequency of 2.4576 MHz. The table opposite
shows the port assignment.
7-6
Port
Port 1
Port 2
Port 3
Port 4
Assignment
Parallel I/O terminal
Serial I/O terminal
Address/data terminal
Address terminal