Sharp CD-BK260V Service Manual page 54

CD-BK260V/CD-BK2700V/CD-BK280V
ICM1 VHi1625635T-1: DRAM (1625635T)
Pin No. Port Name
1 VCC POWER SUPPLY.
2-10 I/O0-I/O7 DATA INPUT/OUTPUT.
11*,12* N.C. NOT USED.
13 WE READ/WRITE ENABLE.
14 RAS ROW ADDRESS STROBE.
15* N.C. NOT USED.
16-19 A0-A3 ADDRESS INPUT. (ROW/REFRESH: A0 TO A3) (COLUMN: A0 TO A3)
20 VCC POWER SUPPLY.
21 VSS GROUND.
22-26 A4-A8 ADDRESS INPUT. (ROW/REFRESH: A4 TO A8) (COLUMN: A4 TO A8)
27 OE OUTPUT ENABLE.
28,29 UCAS,LCAS COLUMN ADDROSS STROBE.
30* N.C. NOT USED.
31-34 I/O8-11 DATA INPUT/OUTPUT.
35 VSS GROUND.
36-39 I/O12-15 DATA INPUT/OUTPUT.
40 VSS GROUND.
In this unit, the terminal with asterisk mark (*) is (open) terminal which is not connected to the outside.
RAS
14
29
LCAS
28
UCAS
13
WE
A0 16
17
A1
A2
18
19
A3
A4
22
23
A5
A6 24
A7
25
A8
26
Clock generating
circuit
A0-A8
Memory cell array
A0-A8
Figure 54 BLOCK DIAGRAM OF IC
Function
Lowar
Upper
Coidmn decoder
I/O control circuit
– 54 –
Lower data
Input buffer
Lower data
Output buffer
Upper data
Input buffer
Upper data
Output buffer
1
VCC
20
40
35
VSS
21
2
I/O0
3
I/O1
10
I/O7
31
I/O8
32
I/O9
39
I/O15
27
OE