HD6433308 HITACHI [Hitachi Semiconductor], HD6433308 Datasheet - Page 240

• Manufacturer Part Number: HD6433308
• Description: Hitachi Single-Chip MicroComputer
• Manufacturer: HITACHI [Hitachi Semiconductor]

System Control Register (SYSCR)—H’FFC4
Bit
Initial value
Read/Write
The only bit in the system control register that concerns the dual-port RAM is the DPME bit. See
section 2.4.2, "System Control Register" for the other bits.
Bit 1 – Dual-Port RAM Enable (DPME): This bit enables or disables the dual-port RAM. The
dual-port RAM can be enabled only in the single-chip mode (mode 3).
Bit 1
DPME
If the DPME bit is set to “1” while the H8/330 is operating in the single-chip mode, the following
pins are automatically assigned to dual-port RAM functions, regardless of their data direction
register settings:
Port 3 (P3
Port 8 (P8
In port 9,
The DPME bit is initialized to “0” by a reset and in the hardware standby mode.
Setting the DPME bit to "1" in the expanded modes (modes 1 and 2) has no effect.
0
1
7
3
to P3
to P8
Description
The dual-port RAM is disabled.
The dual-port RAM is enabled (in single-chip mode only).
P9
P95
P9
P9
0
0
7
4
3
SSBY
)
)
R/W
7
0
DDB
RS3 to RS0 (dual-port RAM register select; input)
WE (Write Enable; input)
RDY (Ready; output)
OE (Output Enable; input)
CS (Chip Select; input)
7
STS2
R/W
to DDB
6
0
0
STS1
R/W
(parallel communication data bus; input/output)
5
0
STS0
229
R/W
4
0
—
—
3
1
NMIEG DPME
R/W
2
0
R/W
1
0
(Initial value)
RAME
R/W
0
1