Serial Port (Com3, 4) - Panasonic JS-170FR Series Service Manual

2.1.6

Serial port (COM3, 4)

The two 16C550 compatible serial port controllers (COMA and COMB) are incorporated in the PC16552D, independently of each
other.
With the 1.84MHz clock (fixed) supplied from the outside, a Baud rate clock is generated. This port operates in an asynchronous
mode.
The I/O addresses of these two controllers are decoded inside the gate array.
PC16552D
CAMA
COMB
The transmission data signal (TXD3) of the COM3 is used through customer and display changeover. The COM4 is used as an
interface of the touch panel at the TTL level.
System
COM3
COM4
2-26
I/O address
3220~3227h
3228~322Fh
Interrupt level
IRQ11 or IRQ3
IRQ10