Sharp MD-C2 Service Manual page 87

IC1202 RH-iX2474AFZZ: 4bit D-DRAM (iX2474AF)
Terminal Name
Pin No.
1, 2 I/O1, I/O2 Data input/Data output
3 WE Write enable
4 RAS Row address storobe
5 A9 Address input
6-9 A0-A3 Address input
10 Vcc Power (3.3V)
11-15 A4-A8 Address input
16 OE Output enable
17 CAS Column address storobe
18, 19 I/O3, I/O4 Data input/Data output
20 GND Ground
In this unit, the terminal with asterisk mark (*) is (open) terminal which is not connected to the outside.
4
RAS
17
CAS
Row Address
A0 5
Row Address
A9 15
20
V
SS
17
CAS
IC1402 VHiS29294A/-1: EEPROM (S29294A)
Terminal Name
Pin No.
1* NC Not connected
2 Vcc Power
3 CS Chip selection input
4 SK Serial clock input
5 DI Serial data input
6 DO Serial data output
7 GND Ground
8 PROTECT Memory protection input
Connected to GND or open : Protection valid
Connected to VCC : Protection invalid
In this unit, the terminal with asterisk mark (*) is (open) terminal which is not connected to the outside.
PROTECT
Clock Generator
CBR Refresh SELF Refresh
Counter Timer
MN42V4400 ONLY
Row Decoder Word Driver
Buffer
Column Decoder Sense Amp.
Buffer
On ChipVBB
V
BB
Generator
Figure 87-1 BLOCK DIAGRAM OF IC
Memory array
write-
protection
circuit
Data register
DI
Mode decode
CS
SK Clock generating circuit
Figure 87-2 BLOCK DIAGRAM OF IC
Function
Memory
Cell
I/O
Selection
Function
Bank 1
Address
decoder
Bank 2
Output buffer
logic
– 87 –
Write Clock
3
WE
Generator
Data Input
Buffer
I/O1~I/O4
Data Output
16
OE
Buffer
Vcc
GND
DO
MD-C2