HD404339 Datasheet, PDF (31/78 Pages) Hitachi Semiconductor – 4-bit HMCS400-Series microcomputer with large-capacity memory

HD404339 Series
Data control register (DCR0: $030, DCR3 to DCR7: $033 to $037)
DCR0, DCR3
to DCR7
Bit
3
2
1
0
Initial value
Read/Write
Bit name
0
0
0
0
W
W
W
W
DCR03,
DCR33
to
DCR63
DCR02,
DCR32
to
DCR72
DCR01,
DCR31
to
DCR71
DCR00,
DCR30
to
DCR70
Bits 0 to 3 CMOS Buffer Control
0
CMOS buffer off
(high impedance)
1
CMOS buffer on
Correspondence between ports and DCR bits
Register Bit 3 Bit 2 Bit 1 Bit 0
DCR0
R0₃
R0₂
R0₁
R0₀
DCR3
R3₃
R3₂
R3₁
R3₀
DCR4
R4₃
R4₂
R4₁
R4₀
DCR5
R5₃
R5₂
R5₁
R5₀
DCR6
R6₃
R6₂
R6₁
R6₀
DCR7 Not used R7₂
R7₁
R7₀
Figure 22 Data Control Register (DCR)
31