Panasonic JB-3300 Technical Manual page 32

Input/Output
Structure
The computer I/O structure uses the lower eleven bits of an MPU address
when issuing
in addresses
an I/O command, and all I/O addresses are allocated to spaces
OOO (HEX) to 3FF (HEX).
Table 4-1 shows an I/O address map.
Table 4-1 Input/Output Address Map
Hex Range Usage
000 - OOF DMA chip 8237A-5
020 - O21 Interrupt chip 8259A
040 - 043 Timer chip 8253-5
O60 - 063 PPI chip 8255A-5
O80 - 083 DMA page registers
OAX NMI mask register
320 - 323 Hard disk
378 - 37F
or Parallel port (Centronics printer) strap select
278 - 27F
3D0 - 3DF Display (Color/Graphics)
3FO - 3F7 Floppy disk
3F8 - 3FF
or Serial port (Asynchronous communications) Strap select
2F8 - 2FF
I - 14