
No. 6614-9/12
LC898023K
Continued from preceding page.
Pin No.
Pin name
Type
Pin function
185
VSS
P
Digital system ground (VSS)
186
VDD
P
Digital system power supply (5 V)
187
REQ
B
SCSI connections
188
I/O
B
189
VSS
P
Digital system ground (VSS)
190
VDD
P
Digital system power supply (3.3 V)
191
VSS
P
Digital system ground (VSS)
192
NC
Unused
193
NC
Unused
194
RAS0
O
195
RAS1
O
DRAM RAS signal outputs
196
RAS2
O
197
LWE
O
DRAM lower write enable
198
VDD
P
Digital system power supply (3.3 V)
199
VSS
P
Digital system ground (VSS)
200
UWE
O
DRAM upper write enable
201
CAS0
O
DRAM CAS signal output
202
CAS1
O
203
OE
O
DRAM output enable
204
RA0
O
205
RA1
O
CD-ROM encoder/decoder DRAM address lines
206
RA2
O
207
RA3
O
208
VDD
P
Digital system power supply (3.3 V)
Pin Functions
<SCSI Interface Pins>
BSY, ACK, MSG, SEL, REQ, ATN, RST, I/O, C/D (input/output)
SCIS bus control.
DB0 to DB7, DBP (input/output)
SCSI data bus.
<Microcontroller Interface Pins>
CS (input)
Chip select signal from the microcontroller. The microcontroller interface is active when this pin is low.
RD, WR (input)
Connect the microcontroller read and write lines to these inputs.
SWAIT (input)
Wait signal output to the microcontroller. When accessing buffer RAM, the microcontroller must wait if this pin is
low.
SUA0 to SUA7 (input)
Internal register address lines
D0 to D7 (input)
Microcontroller data bus. These pins have built-in pull-up resistors.
INT0, INT1 (output)
Interrupt request signals output to the microcontroller. INT1 can be set to output the ATAPI interrupt by setting
INT1EN (Conf-R11 bit 7)
These are open drain outputs with built-in 80 k
(at room temperature, 5 V) pull-up resistors.
<Buffer RAM Pins>
I/O0 to I/O15 (input/output)
Buffer RAM data bus. These pins have built-in pull-up resistors.
RA0 to RA9 (output)
Buffer RAM address lines.