Oki MSM85C154HVS User Manual

MSM80C154S/83C154S/85C154HVS
32
2.9 Program Counter
The MSM80C154S/MSM83C154S program counter has a 16-bit configuration PC0 thru
PC15, as shown in Figure 2-23.
Q8Q9Q10Q11Q12Q13Q14Q15
D8D9D10D11D12D13D14D15
Q0Q1Q2Q3Q4Q5Q6Q7
D0D1D2D3D4D5D6D7
PC+1
MSM83C154S INTERNAL ROM
16KWORD × 8BIT
CPU INTERNAL DATA BUS
EXTERNAL
ROM MODE
ENABLE ROM
CPU INTERNAL DATA BUS
Figure 2-23 MSM80C154S/MSM83C154S program ounter
This program counter is a binary up-counter which is incremented by 1 each time one byte
of instruction code is fetched. When the program counter is counted by 1 after counter
contents have reached 0FFFFH, the counter is returned to 0000H. MSM83C154S is
automatically switched to external ROM mode when the counter contents exceed 3FFFH.

Oki MSM85C154HVS Specifications

General

Brand	Oki
Model	MSM85C154HVS
Category	Controller
Language	English