MITMSIUTBSUISBHIISHDIIGDITIGAILTAALSSAPSSP
M66220SP/FP
M66220SP/FP
256 × 8-BIT MAIL-BOX
256 × 8-BIT MAIL-BOX
DESCRIPTION
PIN CONFIGURATION (Top view)
The M66220 is a mail box that incorporates a complete CMOS shared
memory cell of 256 × 8-bit configuration using high-performance silicon
gate CMOS process technology, and is equipped with two access
ports of A and B.
CHIP SELECT
INPUT
→
→
←
→
→
→
→
→
→
→
→
→
↔
↔
↔
↔
↔
↔
↔
↔
1
2
42
41
40
39
38
37
36
35
34
33
32
31
30
29
28
27
26
25
24
23
22
VCC
CSA
CHIP SELECT
INPUT
WRITE ENABLE
INPUT
NOT READY
OUTPUT
OUTPUT ENABLE
INPUT
WRITE ENABLE
←
←
→
←
←
←
←
←
←
←
←
←
↔
↔
↔
↔
↔
↔
↔
↔
WEA
CSB
INPUT
NOT READY
OUTPUT
Not Ready A
3
WEB
Access ports A and B are equipped with independent addresses CS,
WE and OE control pins and I/O pins to allow independent and
asynchronous read/write operations from/to shared memory
individually. This product also incorporates a port adjustment
arbitration function in address contention from both ports.
OUTPUT ENABLE
INPUT
OEA
4
Not Ready B
A
A
A
A
A
A
A
A
0A
1A
2A
3A
4A
5A
6A
7A
0A
1A
2A
3A
4A
5A
6A
7A
5
OEB
6
A
A
A
A
A
A
A
A
0B
1B
2B
3B
4B
5B
6B
7B
7
A PORT
ADDRESS
INPUT
8
FEATURES
B PORT
ADDRESS
INPUT
• Memory configuration of 256 × 8 bits
• High-speed access, address access time 40ns (typ.)
• Complete asynchronous accessibility from ports A and B
• Completely static operation
9
10
11
12
13
14
15
16
17
18
19
20
21
• Built-in port arbitration function
I/O
I/O
I/O
I/O
I/O
I/O
I/O
I/O
• Low power dissipation CMOS design
• 5V single power supply
I/O
I/O
I/O
I/O
I/O
I/O
I/O
I/O
7
6
5
4
3
2
1
0
B
B
B
B
B
B
B
B
• Not Ready output pin is provided (open drain output)
• TTL direct-coupled I/O
A PORT
DATA I/O
• 3-state output for I/O pins
B PORT
DATA I/O
APPLICATION
Inter-MPU data transfer memory, buffer memory for image processing
system.
GND
42P4B
42P2R-A
Outline
BLOCK DIAGRAM
VCC
42
NOT READY
NOT READY
Not Ready A 3
39 Not Ready B OUTPUT
OUTPUT
WRITE
WRITE
40 WEB
ENABLE INPUT WEA 2
ENABLE INPUT
CONTROL
CIRCUIT
ARBITRATION
CIRCUIT
CONTROL
CIRCUIT
CHIP
CHIP
CSA 1
SELECT INPUT
41 CSB
SELECT INPUT
OUTPUT
ENABLE INPUT
OUTPUT
ENABLE INPUT
OEA 4
38 OEB
I/O
I/O
I/O
I/O
I/O
I/O
I/O
I/O
0
1
2
3
4
5
6
7
A 13
A 14
A 15
A 16
A 17
A 18
A 19
A 20
22 I/O
23 I/O
24 I/O
25 I/O
26 I/O
27 I/O
28 I/O
29 I/O
0
1
2
3
4
5
6
7
B
B
B
B
B
B
B
B
A
0
A
A
A
0
B
OEA
WEA
WEB
OEB
A
7
A
7
B
A PORT DATA I/O
B PORT DATA I/O
8
8
8
8
I/O BUFFER
I/O BUFFER
A
A
A
A
A
A
A
A
0
1
2
3
4
5
6
7
A 5
A 6
A 7
A 8
A 9
A 10
A 11
A 12
37 A
36 A
35 A
34 A
33 A
32 A
31 A
30 A
0B
1B
2B
3B
4B
5B
6B
7B
MEMORY ARRAY OF
256-WORD × 8-BIT
CONFIGURATION
A PORT
ADDRESS INPUT
B PORT
ADDRESS INPUT
ROW/COLUMN
DECODER
ROW/COLUMN
DECODER
21
GND
1