OKI MSM548262-60TS-K

E2L0016-17-Y1
¡ Semiconductor
MSM548262
¡ Semiconductor
This version:
Jan. 1998
MSM548262
Previous version: Dec. 1996
262,144-Word ¥ 8-Bit Multiport DRAM
DESCRIPTION
The MSM548262 is a 2-Mbit CMOS multiport DRAM composed of a 262,144-word by 8-bit
dynamic RAM, and a 512-word by 8-bit SAM. Its RAM and SAM operate independently and
asynchronously.
It supports three types of operations: random access to RAM port, high speed serial access to
SAM port, and bidirectional transfer of data between any selected row in the RAM port and the
SAM port. In addition to the conventional multiport DRAM operating modes, the MSM548262
features block write, flash write functions on the RAM port and a split data transfer capability
on the SAM port. The SAM port requires no refresh operation because it uses static CMOS flipflops.
FEATURES
• RAS only refresh
• Single power supply: 5 V ±10%
• CAS before RAS refresh
• Full TTL compatibility
• Hidden refresh
• Multiport organization
• Serial read/write
RAM : 256K word ¥ 8 bits
• 512 tap location
SAM : 512 word ¥ 8 bits
• Bidirectional data transfer
• Fast page mode
• Split transfer
• Write per bit
• Masked write transfer
• Masked flash write
• Refresh: 512 cycles/8 ms
• Masked block write
• Package options:
40-pin 400 mil plastic SOJ
(SOJ40-P-400-1.27)
(Product : MSM548262-xxJS)
44/40-pin 400 mil plastic TSOP (Type II)(TSOPII44/40-P-400-0.80-K)(Product : MSM548262-xxTS-K)
xx indicates speed rank.
PRODUCT FAMILY
Family
Access Time
Cycle Time
Power Dissipation
RAM
SAM
RAM
SAM
Operating
Standby
MSM548262-60
60 ns
17 ns
120 ns
22 ns
140 mA
8 mA
MSM548262-70
70 ns
17 ns
140 ns
22 ns
130 mA
8 mA
MSM548262-80
80 ns
20 ns
150 ns
25 ns
120 mA
8 mA
1/37
¡ Semiconductor
MSM548262
PIN CONFIGURATION (TOP VIEW)
VCC
1
40
VSS
SC
2
39
SDQ8
SDQ1
3
38
SDQ7
SDQ2
4
37
SDQ6
SDQ3
5
36
SDQ5
SDQ4
6
35
SE
TRG
7
34
DQ8
DQ1
8
33
DQ7
DQ2
9
32
DQ6
DQ3
10
31
DQ5
DQ4
11
30
VSS
VSS
12
29
DSF
WE
13
28
NC
RAS
14
27
CAS
A8
15
26
QSF
A7
16
25
A0
A6
17
24
A1
A5
18
23
A2
A4
19
22
A3
VCC
20
21
VSS
VCC
SC
SDQ1
SDQ2
SDQ3
SDQ4
TRG
DQ1
DQ2
DQ3
1
2
3
4
5
6
7
8
9
10
44
43
42
41
40
39
38
37
36
35
VSS
SDQ8
SDQ7
SDQ6
SDQ5
SE
DQ8
DQ7
DQ6
DQ5
DQ4
VSS
WE
RAS
A8
A7
A6
A5
A4
VCC
13
14
15
16
17
18
19
20
21
22
32
31
30
29
28
27
26
25
24
23
VSS
DSF
NC
CAS
QSF
A0
A1
A2
A3
VSS
44/40-Pin Plastic TSOP (II)
(K Type)
40-Pin Plastic SOJ
Pin Name
A0 - A8
Function
Address Input
Pin Name
Function
SC
Serial Clock
DQ1 - DQ8
RAM Inputs/Outputs
SE
SAM Port Enable
SDQ1 - SDQ8
SAM Inputs/Outputs
DSF
Special Function Input
RAS
Row Address Strobe
QSF
Special Function Output
CAS
Column Address Strobe
VCC
Power Supply (5 V)
WE
Write Enable
VSS
Ground (0 V)
TRG
Transfer/Output Enable
NC
No Connection
Note:
The same power supply voltage must be provided to every VCC pin, and the same GND
voltage level must be provided to every VSS pin.
2/37
Block Write
Control
Column Mask
Register
Sense Amp.
I/O Control
Color Register
RAM Input
Buffer
Mask Register
A0 - A8
Refresh
Counter
Row Decoder
Row
Address
Buffer
512 ¥ 512 ¥ 8
RAM ARRAY
Gate
Gate
SAM
SAM
Serial Decoder
SAM
Address
Buffer
¡ Semiconductor
Column Decoder
BLOCK DIAGRAM
Column
Address
Buffer
DQ 1 - 8
RAM Output
Buffer
Flash Write
Control
SAM Input
Buffer
RAS
CAS
SDQ 1 - 8
SAM Output
Buffer
Timing
Generator
TRG
WE
DSF
SC
SAM Address
Counter
SE
VCC
VSS
3/37
MSM548262
SAM Stop
Control
QSF
¡ Semiconductor
MSM548262
ELECTRICAL CHARACTERISTICS
Absolute Maximum Ratings
(Note: 1)
Parameter
Symbol
Condition
Rating
Unit
Input Output Voltage
VT
Ta = 25°C
–1.0 to 7.0
V
Output Current
IOS
Ta = 25°C
50
mA
Power Dissipation
PD
Topr
Ta = 25°C
1
W
Operating Temperature
—
0 to 70
°C
Storage Temperature
Tstg
—
–55 to 150
°C
Recommended Operating Conditions
(Ta = 0°C to 70°C) (Note: 2)
Parameter
Symbol
Min.
Typ.
Max.
Unit
Power Supply Voltage
VCC
4.5
5.0
5.5
V
Input High Voltage
VIH
2.4
—
6.5
V
Input Low Voltage
VIL
–1.0
—
0.8
V
Capacitance
(VCC = 5 V ±10%, f = 1 MHz, Ta = 25°C)
Parameter
Input Capacitance
Input/Output Capacitance
Output Capacitance
Note:
Symbol
Min.
Max.
Unit
Ci
—
8
pF
Cio
—
9
pF
Co(QSF)
—
9
pF
This parameter is periodically sampled and is not 100% tested.
DC Characteristics 1
Symbol
Condition
Min.
Max.
Output "H" Level Voltage
Parameter
VOH
IOH = –1 mA
2.4
—
Output "L" Level Voltage
VOL
IOL = 2.1 mA
—
0.4
Input Leakage Current
ILI
0 £ VIN £ VCC
All other pins not
under test = 0 V
–10
10
0 £ VOUT £ 5.5 V
Output Disable
–10
Output Leakage Current
ILO
Unit
V
mA
10
4/37
¡ Semiconductor
MSM548262
DC Characteristics 2
(VCC = 5 V ±10%, Ta = 0°C to 70°C)
Item (RAM)
Operating Current
(RAS, CAS Cycling, tRC = tRC min.)
Standby Current
(RAS, CAS = VIH)
RAS Only Refresh Current
(RAS Cycling, CAS = VIH, tRC = tRC min.)
Page Mode Current
(RAS = VIL, CAS Cycling, tPC = tPC min.)
CAS before RAS Refresh Current
(RAS Cycling, CAS before RAS, tRC = tRC min.)
Data Transfer Current
(RAS, CAS Cycling, tRC = tRC min.)
Flash Write Current
(RAS, CAS Cycling, tRC = tRC min.)
Block Write Current
(RAS, CAS Cycling, tRC = tRC min.)
-60
-70
-80
SAM
Symbol
Standby
ICC1
95
85
75
3, 4
17
Max. Max. Max.
Active
ICC1A
140
130
120
Standby
ICC2
8
8
8
Unit Note
Active
ICC2A
60
55
50
3, 4
Standby
ICC3
95
85
75
3, 4
Active
ICC3A
140
130
120
17
Standby
ICC4
75
70
65
3, 4
Active
ICC4A
140
130
120
Standby
ICC5
95
85
75
Active
ICC5A
140
130
120
3, 4
mA
18
3, 4
Standby
ICC6
95
85
75
3, 4
Active
ICC6A
140
130
120
17
Standby
ICC7
95
85
75
3, 4
Active
ICC7A
140
130
120
3, 4
Standby
ICC8
95
85
75
3, 4
Active
ICC8A
140
130
120
3, 4
5/37
¡ Semiconductor
MSM548262
AC Characteristics (1/3)
Parameter
Symbol
-60
-70
-80
Min. Max. Min. Max. Min. Max.
Unit Note
tRC
120
—
140
—
150
—
ns
tRWC
170
—
185
—
195
—
ns
tPC
40
—
45
—
50
—
ns
tPRWC
85
—
90
—
90
—
ns
tRAC
—
60
—
70
—
80
ns
8, 14
Access Time from Column Address
tAA
—
30
—
35
—
40
ns
8, 14
Access Time from CAS
tCAC
—
15
—
20
—
25
ns
8, 15
Access Time from CAS Precharge
tCPA
—
35
—
40
—
45
ns
8, 15
Output Buffer Turn-off Delay
tOFF
0
15
0
20
0
20
ns
10
7
Random Read or Write Cycle Time
Read Modify Write Cycle
Fast Page Mode Cycle Time
Fast Page Mode Read Modify Write Cycle Time
Access Time from RAS
Transition Time (Rise and Fall)
tT
3
35
3
35
3
35
ns
RAS Precharge Time
tRP
50
—
60
—
60
—
ns
RAS Pulse Width
tRAS
60
10k
70
10k
80
10k
ns
RAS Pulse Width (Fast Page Mode Only)
tRASP
60
100k
70
100k
80
100k
ns
RAS Hold Time
tRSH
15
—
20
—
25
—
ns
CAS Hold Time
tCSH
60
—
70
—
80
—
ns
CAS Pulse Width
tCAS
15
10k
20
10k
25
10k
ns
RAS to CAS Delay Time
tRCD
20
45
20
50
20
55
ns
14
RAS to Column Address Delay Time
tRAD
15
30
15
35
15
40
ns
14
Column Address to RAS Lead Time
tRAL
30
—
35
—
40
—
ns
CAS to RAS Precharge Time
tCRP
10
—
10
—
10
—
ns
CAS Precharge Time (Fast Page Mode)
tCP
10
—
10
—
10
—
ns
Row Address Set-up Time
tASR
0
—
0
—
0
—
ns
Row Address Hold Time
tRAH
10
—
10
—
10
—
ns
Column Address Set-up Time
tASC
0
—
0
—
0
—
ns
Column Address Hold Time
tCAH
10
—
10
—
12
—
ns
Column Address Hold Time referenced to RAS
tAR
50
—
55
—
55
—
ns
Read Command Set-up Time
tRCS
0
—
0
—
0
—
ns
Read Command Hold Time
tRCH
0
—
0
—
0
—
ns
11
Read Command Hold Time referenced to RAS
tRRH
0
—
0
—
0
—
ns
11
13
Write Command Set-up Time
tWCS
0
—
0
—
0
—
ns
Write Command Hold Time
tWCH
10
—
12
—
15
—
ns
Write Command Hold Time referenced to RAS
tWCR
50
—
55
—
55
—
ns
Write Command Pulse Width
tWP
10
—
12
—
15
—
ns
Write Command to RAS Lead Time
tRWL
15
—
20
—
20
—
ns
Write Command to CAS Lead Time
tCWL
15
—
20
—
20
—
ns
Data Set-up Time
tDS
0
—
0
—
0
—
ns
12
Data Hold Time
tDH
10
—
12
—
15
—
ns
12
Data Hold Time referenced to RAS
tDHR
50
—
55
—
55
—
ns
6/37
¡ Semiconductor
MSM548262
AC Characteristics (2/3)
Parameter
Symbol
-60
-70
-80
Min. Max. Min. Max. Min. Max.
RAS to WE Delay Time
tRWD
80
—
90
Column Address to WE Delay Time
tAWD
50
—
CAS to WE Delay Time
tCWD
35
—
Data to CAS Delay Time
tDZC
0
Data to TRG Delay Time
tDZO
0
Access Time from TRG
tOEA
—
Output Buffer Turn-off Delay from TRG
tOEZ
0
TRG Command Hold Time
tOEH
10
—
RAS Hold Time referenced to TRG
tROH
10
—
Unit Note
—
100
—
ns
13
55
—
65
—
ns
13
40
—
45
—
ns
13
—
0
—
0
—
ns
—
0
—
0
—
ns
15
—
20
—
20
ns
10
0
10
0
10
ns
10
—
10
—
ns
15
—
15
—
ns
CAS Set-up Time for CAS before RAS Cycle
tCSR
10
—
10
—
10
—
ns
CAS Hold Time for CAS before RAS Cycle
tCHR
10
—
10
—
10
—
ns
RAS Precharge to CAS Active Time
tRPC
0
—
0
—
0
—
ns
Refresh Period
tREF
—
8
—
8
—
8
ms
WE Set-up Time
tWSR
0
—
0
—
0
—
ns
WE Hold Time
tRWH
10
—
10
—
12
—
ns
DSF Set-up Time referenced to RAS
tFSR
0
—
0
—
0
—
ns
DSF Hold Time referenced to RAS (1)
tRFH
10
—
10
—
12
—
ns
DSF Hold Time referenced to RAS (2)
tFHR
50
—
55
—
55
—
ns
DSF Set-up Time referenced to CAS
tFSC
0
—
0
—
0
—
ns
DSF Hold Time referenced to CAS
tCFH
10
—
10
—
12
—
ns
Write Per Bit Mask Data Set-up Time
tMS
0
—
0
—
0
—
ns
Write Per Bit Mask Data Hold Time
tMH
10
—
10
—
12
—
ns
TRG High Set-up Time
tTHS
0
—
0
—
0
—
ns
TRG High Hold Time
tTHH
10
—
10
—
12
—
ns
TRG Low Set-up Time
tTLS
0
—
0
—
0
—
ns
TRG Low Hold Time
tTLH
10
10k
10
10k
12
10k
ns
TRG Low Hold Time referenced to RAS
tRTH
50
10k
60
10k
65
10k
ns
TRG Low Hold Time referenced to Column Address
tATH
20
—
25
—
30
—
ns
TRG Low Hold Time referenced to CAS
tCTH
15
—
20
—
25
—
ns
TRG to RAS Precharge Time
tTRP
50
—
60
—
60
—
ns
TRG Precharge Time
tTP
20
—
20
—
20
—
ns
RAS to First SC Delay Time (Read Transfer)
tRSD
60
—
70
—
80
—
ns
Column Address to First SC Delay Time
tASD
40
—
45
—
45
—
ns
CAS to First SC Delay Time (Read Transfer)
tCSD
20
—
20
—
25
—
ns
Last SC to TRG Lead Time
tTSL
5
—
5
—
5
—
ns
TRG to First SC Delay Time (Read Transfer)
tTSD
15
—
15
—
15
—
ns
Last SC to RAS Set-up Time (Serial Input)
tSRS
20
—
25
—
25
—
ns
Serial Output Buffer Turn-off Delay from RAS
tSDZ
10
30
10
40
10
40
ns
10
7/37
¡ Semiconductor
MSM548262
AC Characteristics (3/3)
Parameter
SC Cycle Time
Symbol
-60
-70
-80
Min. Max. Min. Max. Min. Max.
Unit Note
tSCC
22
—
22
—
25
—
ns
SC Pulse Width (SC High Time)
tSC
5
—
5
—
SC Precharge Time (SC Low Time)
tSCP
5
—
5
—
7
—
ns
7
—
ns
Access Time from SC
tSCA
—
17
—
17
—
20
ns
9
Serial Output Hold Time from SC
tSOH
5
—
5
—
5
—
ns
19
Access Time from SE
tSEA
—
17
—
17
—
20
ns
9
SE Pulse Width
tSE
10
—
10
—
10
—
ns
SE Precharge Time
tSEP
10
—
10
—
10
—
ns
Serial Output Buffer Turn-off Delay from SE
tSEZ
0
20
0
20
0
20
ns
Split Transfer Set-up Time
tSTS
25
—
25
—
30
—
ns
Split Transfer Hold Time
tSTH
25
—
25
—
30
—
ns
SC-QSF Delay Time
tSQD
—
25
—
25
—
25
ns
TRG-QSF Delay Time
tTQD
—
25
—
25
—
25
ns
CAS-QSF Delay Time
tCQD
—
30
—
35
—
35
ns
RAS-QSF Delay Time
tRQD
—
70
—
75
—
75
ns
RAS to Serial Input Delay Time
tSDD
30
—
40
—
40
—
ns
Serial Input Set-up Time
tSDS
0
—
0
—
0
—
ns
Serial Input Hold Time
tSDH
10
—
10
—
12
—
ns
Serial Input to SE Delay Time
tSZE
0
—
0
—
0
—
ns
Serial Input to First SC Delay Time
tSZS
0
—
0
—
0
—
ns
Serial Write Enable Set-up Time
tSWS
0
—
0
—
0
—
ns
Serial Write Enable Hold Time
tSWH
10
—
10
—
12
—
ns
Serial Write Disable Set-up Time
tSWIS
0
—
0
—
0
—
ns
Serial Write Disable Hold Time
tSWIH
10
—
10
—
12
—
ns
10
8/37
¡ Semiconductor
Notes:
MSM548262
1. Exposure beyond the "Absolute Maximum Ratings" may cause permanent damage
to the device.
2. All voltages are referenced to VSS.
3. These parameters depend on the cycle rate.
4. These parameters depend on output loading. Specified values are obtained with the
output open.
5. An initial pause of 200 ms is required after power up followed by any 8 RAS cycles
(TRG = "high") and any 8 SC cycles before proper device operation is achieved.
In the case of using an internal refresh counter, a minimum of 8 CAS before RAS
cycles instead of 8 RAS cycles are required.
6. AC measurements assume tT = 5 ns.
7. VIH (Min.) and VIL (Max.) are reference levels for measuring timing of input signals.
Also, transition times are measured between VIH and VIL.
8. RAM port outputs are measured with a load equivalent to 1 TTL load and 50 pF.
DOUT reference levels : VOH/VOL = 2.0 V/0.8 V.
9. SAM port outputs are measured with a load equivalent to 1 TTL load and 30 pF.
DOUT reference levels : VOH/VOL = 2.0 V/0.8 V.
10. tOFF (Max.), tOEZ (Max.), tSDZ (Max.) and tSEZ (Max.) define the time at which the
outputs achieve the open circuit condition, and are not referenced to output voltage
levels. This parameter is sampled and not 100% tested.
11. Either tRCH or tRRH must be satisfied for a read cycle.
12. These parameters are referenced to CAS leading edge of early write cycles, and to
WE leading edge in TRG controlled write cycles and read modify write cycles.
13. tWCS, tRWD, tCWD and tAWD are not restrictive operating parameters.
They are included in the data sheet as electrical characteristics only.
If tWCS ≥ tWCS (Min.), the cycle is an early write cycle, and the data out pin will
remain open circuit throughout the entire cycle; If tRWD ≥ tRWD (Min.), tCWD ≥ tCWD
(Min.) and tAWD ≥ tAWD (Min.), the cycle is a read modify write cycle, and the data
out will contain data read from the selected cell; If neither of the above sets of
conditions are satisfied, the condition of the data out is indeterminate.
14. Operation within the tRCD (Max.) limit ensures that tRAC (Max.) can be met.
tRCD (Max.) is specified as a reference point only: If tRCD is greater than the specified
tRCD (Max.) limit, then access time is controlled by tCAC.
15. Operation within the tRAD (Max.) limit ensures that tRAC (Max.) can be met. tRAD
(Max.) is specified as a reference point only: If tRAD is greater than the specified tRAD
(Max.) limit, then access time is controlled by tAA.
16. Input levels at the AC testing are 3.0 V/0 V.
17. Address (A0 - A8) may be changed two times or less while RAS = VIL.
18. Address (A0 - A8) may be changed once or less while CAS = VIH and RAS = VIL.
19. This is guaranteed by design. (tSOH/tCOH = tSCA/tCAC - output transition time)
This parameter is not 100% tested.
9/37
¡ Semiconductor
MSM548262
TIMING WAVEFORM
Read Cycle
tRC
tRAS
RAS
tRP
,
,,
,,
tCSH
tCRP
CAS
tAR
tRAD
tASR
Address
tRSH
tCAS
tRCD
tRAL
tRAH
tASC
Row
tCAH
Column
tFHR
tFSR
DSF
tRFH
tFSC
tCFH
tRCH
tRCS
WE
tRRH
tCAC
tOFF
tRAC
tAA
DQ1 - 8
Open
Valid Data
tROH
tTHS
TRG
tTHH
tOEA
tOEZ
"H" or "L"
10/37
¡ Semiconductor
MSM548262
Fast Page Mode Read Cycle
tRASP
RAS
,,
,,
,
tCSH
tCRP
CAS
tPC
tRCD
tCAS
tCP
tRSH
tCAS
tCP
tCAS
tAR
tRAD
tASR
Address
tRP
tRAL
tRAH
tASC
Row
tCAH
tASC
tCAH
tASC
Column
Column
tCAH
Column
tFHR
tFSR
DSF
tRFH
tFSC
tCFH
tRCS
WE
tFSC tCFH
tFSC tCFH
tRCS
tRCS
tRCH
tCAC
tCAC
Valid
Data
Open
tRAC
TRG
tTHH
tCAC
tAA
tOFF
tTHS
tRRH
tRCH
tAA
DQ1 - 8
tAA
tOFF
tOEZ
tOFF
Valid
Data
tCPA
tOEA
tRCH
Valid
Data
tCPA
tOEA tOEZ
tOEA tOEZ
"H" or "L"
11/37
¡ Semiconductor
MSM548262
Write Cycle Function Table
RAS Falling Edge
Code
A
C
DSF WE
CAS Falling Edge
D
B
E
Function
DQ
DSF
DQ
RWM
0
0
Write Mask
0
Valid Data
BWM
0
0
Write Mask
1
Column Mask
Masked Block Write
FWM
1
0
Write Mask
X
X
Masked Flash Write
RW
0
1
X
0
Valid Data
BW
0
1
X
1
Column Mask
LCR
1
1
X
1
Color Data
Masked Write
Normal Write
Block Write
Load Color Register
WRITE MASK DATA: "Low" = Mask, "High" = No Mask
Column Mask Data
DQ1 - 4
Column Mask Data
DQ1
Column 0 (A0 = 0, A1 = 0)
DQ2
Column 1 (A0 = 1, A1 = 0)
Low: Mask
DQ3
Column 2 (A0 = 0, A1 = 1)
High: No Mask
DQ4
Column 3 (A0 = 1, A1 = 1)
12/37
¡ Semiconductor
MSM548262
Early Write Cycle
tRC
tRAS
RAS
tRP
,
,,
,
,,,
tCSH
tCRP
CAS
tAR
tRAD
tRAL
tRAH
tASR
Address
tRSH
tCAS
tRCD
tASC
Row
tCAH
Column
tFHR
tRFH
tFSR
DSF
tFSC
A
tCFH
B
tCWL
WE
tRWL
tRWH
tWSR
tWP
C
tWCR
tWCS
tMH
tMS
DQ1 - 8
D
tTHS
TRG
tWCH
tDHR
tDS
tDH
E
tTHH
"H" or "L"
13/37
¡ Semiconductor
MSM548262
Late Write Cycle
tRC
tRAS
RAS
tRP
,
,,
,
,,
tCSH
tCRP
CAS
tAR
tRAD
tRAH
tASR
Address
tRSH
tCAS
tRCD
tRAL
tASC
Row
tCAH
Column
tFHR
tRFH
tFSR
DSF
tFSC
A
tCFH
B
tCWL
tRWH
tWSR
WE
tRWL
tRCS
tWP
C
tWCR
tDHR
tMH
tMS
DQ1 - 8
D
tTHS
TRG
tDS
tDH
E
tOEH
"H" or "L"
14/37
¡ Semiconductor
MSM548262
Read Modify Write Cycle
tRWC
tRAS
RAS
tRP
,
,,
,
,,
tCSH
tCRP
CAS
tAR
tRAD
tRAL
tRAH
tASR
Address
tRSH
tCAS
tRCD
tASC
Row
Column
tAWD
tFHR
tRFH
tFSR
DSF
tCAH
tFSC
A
tCFH
B
tCWL
tRWH
tWSR
WE
tRCS
tCWD
tRWL
tWP
tCAC
C
tRWD
tRAC
tMH
tMS
DQ1 - 8
tDZC
tDS
Valid
Data
D
tDH
E
tDZO
tTHS
TRG
tTHH
tOEA tOEZ
tOEH
"H" or "L"
15/37
¡ Semiconductor
MSM548262
Fast Page Mode Early Write Cycle
tRASP
tRP
RAS
tCSH
tCRP
tCAS
tRCD
CAS
tPC
tCP
tCAS
tRSH
tCP
tCAS
tAR
tRAL
tRAD
,
,
,
tASR tRAH
Address
tASC
Row
tCAH
tASC
Column
tCAH
tASC
Column
tCAH
Column
tFHR
tFSR
DSF
tRFH
tFSC tCFH
A
tFSC
B
tCFH
B
tCWL
tWSR tRWH
WE
tWCS
C
tMS
DQ1 - 8
tMH
D
tTHS
tDS
E
tFSC
tCFH
B
tCWL
tCWL
tWCH
tWP
tWCS
tWCH
tWP
tWCS
tWCH
tWP
tDH
tDS
tDH
tDS
tDH
E
E
tTHH
TRG
"H" or "L"
16/37
¡ Semiconductor
MSM548262
Fast Page Mode Read Modify Write Cycle
tRASP
tRP
RAS
tCSH
tCRP
tPRWC
tCAS
tRCD
CAS
tCP
tRSH
tCAS
tCP
tCAS
tAR
tRAL
tRAD
,
,
,
tASR
Address
tRAH
tASC
tASC
tCAH
Row
Column
tASC
tCAH
Column
tCAH
Column
tFHR
tFSR
DSF
tRFH
A
B
tWSR
WE
B
tRCS
tMH
B
tCWL
tAWD
tCWD
tWP
tCAC
tCAC
tCAC
tDH
Out
tTHH
tOEA
tDH
tAA
In
Out
tDS
In
Out
tOEZ
tOEA
tDH
tAA
tDS
tOEZ
tTHS
tCWL
tAWD
tCWD
tWP
tDS
D
tCFH
tCWD
tWP
tAA
tMS
tFSC
tCFH
tCWL
tAWD
tRWH
C
DQ1 - 8
tFSC
tFSC tCFH
In
tOEZ
tOEA
TRG
"H" or "L"
17/37
¡ Semiconductor
MSM548262
RAS Only Refresh Cycle
tRC
tRAS
RAS
tRP
,
,,,
,
,,,
tCRP
CAS
tASR
Address
WE
DQ1 - 8
tRFH
Open
tTHS
TRG
tRAH
Row
tFSR
DSF
tRPC
tTHH
"H" or "L"
18/37
¡ Semiconductor
MSM548262
CAS before RAS Refresh Cycle
tRC
tRP
RAS
Address
DSF
WE
tRP
,,,,
,,,,
tRPC
CAS
tRAS
tCSR
tCHR
tRPC
Inhibit Falling Transition
tOFF
DQ1 - 8
TRG
Open
"H" or "L"
19/37
¡ Semiconductor
MSM548262
Hidden Refresh Cycle
tRC
tRAS
RAS
tRCD
tRSH
tAR
tRAD
tASR
Address
tRAS
,,
,,
,,
tCRP
CAS
tRP
tRAH
tCHR
tRAL
tASC
Row
tCAH
Column
tFHR
tFSR
DSF
tRFH
tFSC
tRCS
WE
tCFH
tRRH
tCAC
tAA
DQ1 - 8
tOFF
Open
Valid Data
tRAC
tTHS
TRG
tTHH
tOEA
tOEZ
"H" or "L"
20/37
¡ Semiconductor
MSM548262
Read Transfer 1
tRC
tRAS
RAS
tRP
,
,,,
tCSH
tRSH
tCAS
tRCD
CAS
tAR
tRAD
Address
Row
tFSR
DSF
tRAL
tASC
tRAH
tASR
tCAH
SAM Start
tRFH
tWSR tRWH
WE
tASD
tCSD
DQ1 - 8
tRSD
Open
tTRP
tTLS
TRG
tTLH
tTP
tSC
tTSD
tSCP
tSRS
SC
Note 2
tSIS
SDQ1 - 8
tSCA
tSZS
tSIH
tSCA
tSOH
Data Out
Din
tRQD
QSF
tSCC
tSC
tCQD
Note 3
tTQD
Note 3
"H" or "L"
Note 1: SE = "L"
Note 2: There must be no rising transitions
Note 3: QSF = "L"-- Lower SAM (0 - 255) is active
QSF = "H"-- Upper SAM (256 - 511) is active
21/37
¡ Semiconductor
MSM548262
Read Transfer 2 (Real Time Read Transfer)
tRC
tRAS
RAS
tRP
,
,,,
tCSH
tRSH
tCAS
tRCD
CAS
tAR
tRAD
Address
Row
tFSR
DSF
tASC
tRAH
tASR
tRAL
tCAH
SAM Start
tRFH
tWSR tRWH
WE
tCTH
tATH
DQ1 - 8
Open
tTRP
tTLS
TRG
tTP
tRTH
tSCC
tSCP
SC
tTSL
tSC
tTSD
tSCA
tSOH
SDQ1 - 8
tSCA
tSOH
Data Out
Data Out
Data Out
Data Out
tTQD
QSF
Note 2
Note 2
"H" or "L"
Note 1: SE = "L"
Note 2: QSF = "L"-- Lower SAM (0 - 255) is active
QSF = "H"-- Upper SAM (256 - 511) is active
22/37
¡ Semiconductor
MSM548262
Split Read Transfer
tRC
tRAS
RAS
tRP
,
,,,
tCSH
tRSH
tCAS
tRCD
CAS
tAR
tRAD
tASR
Address
tRAL
tASC
Row
tFSR
DSF
tRAH
tCAH
SAM Start Sj
tRFH
tWSR tRWH
WE
tCTH
tATH
DQ1 - 8
tTLS
TRG
tTLH
tSCC
tSCP
tSC
tSTS
SC
SDQ1 - 8
Open
tRTH
511
(255)
tSCA
tSOH
Data Out
254
(510)
255
(511)
Data Out
Data Out
Si
(Si+256)
tSCA
tSOH
Data Out
Data Out
tSQD
QSF
Note 2
Sj+256
(S j)
Data Out
tSQD
Note 2
Note 2
"H" or "L"
Note 1: SE = "L"
Note 2: QSF = "L"-- Lower SAM (0 - 255) is active
QSF = "H"-- Upper SAM (256 - 511) is active
Note 3: Si is the SAM start address in before SRT
23/37
¡ Semiconductor
MSM548262
Masked Write Transfer
tRC
tRAS
RAS
tRP
,
,,,
tCSH
tRSH
tCAS
tRCD
CAS
tAR
tRAD
tASR
Address
tASC
tRAH
Row
tFSR
DSF
tRAL
tCAH
SAM Start
tRFH
tWSR tRWH
WE
tMS
DQ1 - 8
tCSD
tMH
Open
Mask Data
tRSD
tTLS
TRG
tTLH
tSRS
tSCC
tSC
SC
tSCP
tSC
Note 2
tSDZ
tSDS
tSOH
SDQ1 - 8
Dout
Dout
tSDH
tSDS
Data In
tSDD
tSDH
Data In
tCQD
tRQD
QSF
Note 3
Note 3
"H" or "L"
Note 1: SE = "L"
Note 2: There must be no rising transitions
Note 3: QSF = "L"-- Lower SAM (0 - 255) is active
QSF = "H"-- Upper SAM (256 - 511) is active
24/37
¡ Semiconductor
MSM548262
Masked Split Write Transfer
tRC
tRAS
RAS
tRP
,
,,,
tCSH
tRSH
tCAS
tRCD
CAS
tAR
tRAD
tASR
Address
tASC
tRAH
Row
tFSR
DSF
tRAL
tCAH
SAM Start Sj
tRFH
tWSR tRWH
WE
tMS
DQ1 - 8
Mask Data
tTLS
TRG
tCTH
tATH
tMH
Open
tRTH
tTLH
tSCC
tSTS
tSCP
SC
511
(255)
Si
(Si+256)
tSDS
SDQ1 - 8
Data In
tSC
tSDH
Data In
254
(510)
tSDS
Sj+256
(S j)
tSDH
Data In
Data In
tSQD
QSF
255
(511)
Note 2
Data In
Data In
tSQD
Note 2
Note 2
"H" or "L"
Note 1: SE = "L"
Note 2: QSF = "L"-- Lower SAM (0 - 255) is active
QSF = "H"-- Upper SAM (256 - 511) is active
Note 3: Si is the SAM start address in before SWT
25/37
¡ Semiconductor
MSM548262
Serial Read Cycle
tSEP
SE
tSCC
tSC
SC
tSCA
tSCP
tSOH
SDQ1 - 8
tSEA
tSEZ
Data Out
Data
tSCA
tSCA
tSOH
tSOH
Data
Data Out
Data Out
Serial Write Cycle
tSEP
SE
tSCC
tSC
SC
tSWH
Data In
tSWIH
tSWS
tSCP
tSDS
SDQ1 - 8
tSWIS
tSDH
Data In
tSZE
tSDS
tSDH
Data In
Data In
"H" or "L"
26/37
¡ Semiconductor
MSM548262
PIN FUNCTIONS
Address Input: A0 - A8
The 18 address bits decode 8 bits of the 2,097,152 locations in the MSM548262 memory array. The
address bits are multiplexed to 9 address input pins (A0 - A8) as standard DRAM. 9 row address
bits are latched at the falling edge of RAS. The following 9 column address bits are latched at the
falling edge of CAS.
Row Address Strobe: RAS
RAS is a basic RAM control signal. The RAM port is in standby mode when the RAS level is
"high". As the standard DRAM’s RAS signal function, RAS is the control input that latches the
row address bits, and a random access cycle begins at the falling edge of RAS.
In addition to the conventional RAS signal function, the level of the input signals CAS, TRG, WE
and DSF at the falling edge of RAS, determines the MSM548262 operation mode.
Column Address Strobe: CAS
As the standard DRAM’s CAS signal function, CAS is the control input signal that latches the
column address input and the state of the special function input DSF to select in conjunction with
the RAS control, either read/write operations or the special block write feature on the RAM port
when the DSF is held "low" at the falling edge of RAS.
CAS also acts as a RAM port output enable signal.
Data Transfer/Output Enable: TRG
TRG is also a control input signal having multiple functions. As the standard DRAM’s OE signal
function, TRG is used as an output enable control when TRG is "high" at the falling edge of RAS.
In addition to the conventional OE signal function, a data transfer operation is started between
the RAM port and the SAM port when TRG is "low" at the falling edge of RAS.
Write Per Bit/Write Enable: WE
WE is a control input signal having multiple functions. As the standard DRAM’s WE signal
function, this is used to write data into the memory on the RAM port when WE is "high" at the
falling edge of RAS.
In addition to the conventional WE signal function, the WE determines the write-per-bit
function, when WE is "low" at the falling edge of RAS during RAM port operations.
The WE also determines the direction of data transfer between the RAM and SAM. When the WE
is "high" at the falling edge of RAS, the data is transferred from RAM to SAM (read transfer).
When the WE is "low" at the falling edge of RAS, the data is transferred SAM to RAM (write
transfer).
27/37
¡ Semiconductor
MSM548262
Write Mask Data/Data Input and Output: DQ1 - DQ8
In conventional write-per bit mode, the DQ pins function as mask data at the falling edge of RAS.
Data is written only to high DQ pins. Data on low DQ pins is masked and internal data is retained.
After that, they function as input/output pins similar to a standard DRAM.
Serial Clock: SC
SC is a main serial cycle control input signal. All operations of the SAM port are synchronized
with the serial clock SC. Data is shifted in or out of the SAM registers at the rising edge of SC. In
a serial read cycle, the output data becomes valid on the SDQ pins after the maximum specified
serial access time tSCA from the rising edge of SC.
In a serial write cycle, data on SDQ pins at the rising edge of SC are fetched into the SAM register.
Serial Enable: SE
The SE is a serial access enable control and serial read/write control signal. In a serial read cycle,
SE is used as an output control. In a serial write cycle, SE is used as a write enable control. When
SE is "high", serial access is disabled. However, the serial address pointer location is still
incremented when SC is clocked even when SE is "high".
Special Function Input: DSF
The DSF is latched at the falling edge of RAS and CAS. It allows for the selection of several RAM
ports and transfer operating modes. In addition to the conventional multiport DRAM, the special
functions consisting of flash write, block write, load/read color register, and split read/write
transfer can be invoked.
Special Function Output: QSF
QSF is an output signal, which during split register mode indicates which half of the split SAM
is being accessed. QSF "low" indicates that the lower split SAM (0 - 255) is being accessed. QSF
"high" indicates that the upper SAM (256 - 511) is being accessed.
Serial Input/Output: SDQ1 - SDQ8
Serial input/output mode is determined by the most recent read or write transfer cycle. When
a read transfer cycle is performed, the SAM port is in the output mode. When a write transfer
cycle is performed, the SAM port is switched from output mode to input mode.
28/37
¡ Semiconductor
MSM548262
OPERATION MODES
Table-1 shows the function truth table for a listing of all available RAM ports, and transfer
operation of MSM548262.
The RAM port and data transfer operations are determined by the state of CAS, TRG, WE and
DSF at the falling edge of RAS, and by the level of DSF at the falling edge of CAS.
Table-1. Function Truth Table
RASØ
Code
CASØ Address
W/IO
CAS TRG WE DSF DSF RASØ CASØ RASØ
CAS
Write
Mask
Color
Register
Function
/WEØ
*
*
*
—
—
CBR Refresh
—
*
—
—
—
RAS Only Refresh
Row TAP WM1
*
Yes
—
Masked Write Transfer
*
Row TAP WM1
*
Yes
—
0
*
Row TAP
*
*
—
—
Read Transfer
1
1
*
Row TAP
*
*
—
—
Split Read Transfer
1
0
0
0
Row Column WM1 Din,Dout
Yes
—
1
1
0
0
1
Row
Yes
Use
Masked Block Write
FWM
1
1
0
1
*
Row
Yes
Use
Masked Flash Write
RW
1
1
1
0
0
Row Column
No
—
BW
1
1
1
0
1
Row
No
Use
—
Load
CBR
0
*
*
*
—
ROR
1
1
*
0
— Row
MWT
1
0
0
0
*
MSWT
1
0
0
1
RT
1
0
1
SRT
1
0
RWM
1
BWM
LCR
1
1
1
1
1
*
Row
Column
A2c - 8c
*
Column
A2c - 8c
*
WM1
Column
Select
WM1 —
*
*
*
Din,Dout
Column
Select
Color
Data
Masked Split
Write Transfer
Read/Write
(Mask)
Read/Write
(No Mask)
Block Write
(No Mask)
Load Color Register
If the DSF is "high" at the falling edge of RAS, special functions such as split transfer, flash write,
load color register can be invoked.
If the DSF is "low" at the falling edge of RAS and "high" at the falling edge of CAS, the block write
feature can be invoked.
29/37
¡ Semiconductor
MSM548262
RAM PORT OPERATION
RAM Read Cycle: RAS falling edge --- TRG = CAS = "H", DSF = "L"
CAS falling edge --- DSF = "L"
Row address is entered at the falling edge of RAS and column address at the falling edge of CAS
to the device as in conventional DRAM. When the WE is "high" and TRG is "low" while CAS is
"low", the data outputs through DQ pins.
RAM Write Cycle: RAS falling edge --- TRG = CAS = "H", DSF = "L"
CAS falling edge --- DSF = "L"
1) Write cycle with no mask: RAS falling edge -- WE = "H"
If WE is set "low" at the falling edge of CAS after RAS goes "low" a write cycle is excuted. If WE
is set "low" before the CAS falling edge, this cycle becomes an early write cycle, and all DQ pins
attain high impedance. All 8 data are latched on the falling edge of CAS.
If WE is set "low" after the CAS falling edge, this cycle becomes a late write cycle, and all 8 data
are latched on the falling edge of WE.
2) Write cycle with mask: RAS falling edge -- WE = "L"
If WE is set "low" at the falling edge of RAS, the mask write mode can be invoked.
Mask data is loaded and used. The mask data on DQ1 - DQ8 is latched into the write mask register
at the falling edge of RAS. When the mask data is low, writing is inhibited into the RAM and the
mask data is high, data is written into the RAM. This mask data is in effect during the RAS cycle.
In page mode cycle the mask data is retained during page access.
30/37
¡ Semiconductor
Load/Read Color Register:
MSM548262
RAS falling edge --- CAS = TRG = WE = DSF = "H"
CAS falling edge --- DSF = "H"
The MSM548262 is provided with an on-chip 8-bit color register for use during the flash write or
block write operation. Each bit of the color register corresponds to one of the DRAM I/O blocks.
The data presented on the DQi lines is subsequently latched into the color register at the falling
edge of either CAS or WE whichever occurs later.
The read color register cycle is activated by holding WE "high" at the falling edge of CAS, and
throughout the remainder of the cycle. The data in the color register becomes valid on the DQi
lines after the specified access times from RAS and TRG are satisfied.
During the load/read color register cycle, the memory cells on the row address latched at the
falling edge of RAS are refreshed.
Flash Write: RAS falling edge --- CAS = TRG = DSF = "H", WE = "L"
Flash write allows for the data in the color register to be written into all the memory locations of
a selected row.
Each bit of the color register corresponds to one of the DRAM I/O blocks. The flash write
operation can be selectively controlled on an I/O basis in the same manner as the write per bit
operation. The mask data is the same as that of a RAM write cycle.
31/37
¡ Semiconductor
MSM548262
Block Write: RAS falling edge --- CAS = TRG = "H", DSF = "L"
CAS falling edge --- DSF = "H"
Block write allows for the data in the color register to be written into 4 consecutive column
address locations, starting from a selected column address in a selected row.
The block write operation can be selectively controlled on an I/O basis, and a column mask
capability is also available. During a block write cycle, the 2 least significant column address
locations (A0C and A1C) are internally controlled, and only the 7 most significant column
addresses (A2C - A8C) are latched at the falling edge of CAS.
1) No mask block write: WE "high" at the falling edge of RAS
The data on 8 DQ pins is all cleared by the data of the color register.
2) Masked block write: WE "low" at the falling edge of RAS
The mask data is the same as that of a RAM write cycle.
SAM PORT OPERATION
Single Register Mode
High speed serial read or write operation can be performed through the SAM port independent
of the RAM port operation, except during read/write transfer cycles.
The preceding transfer operation determines the direction of data flow through the SAM port.
If the preceding transfer is a read transfer, the SAM port is in the output mode. If the preceding
transfer is write transfer, the SAM port is in the input mode.
Serial data can be read out of the SAM after a read transfer has been performed. The data is shifted
out of the SAM starting at any of the 512 bits locations.
The TAP location corresponds to the column address selected at the falling edge of CAS during
the read or write transfer cycle. The SAM registers are configured as a circular data register. The
data is shifted out sequentially. It starts from the selected TAP location at the most significant bit
(511), then wraps around to the least significant bit (0).
Split Register Mode
In split register mode data can be shifted into or out of one half of the SAM, while a split read or
split write transfer is being performed on the other half of the SAM.
Conventional (non split) read, or write transfer cycle must precede any split read or split write
transfers. The split read and write transfers will not change the SAM port mode set by the
preceding conventional transfer operation. In the split register mode, serial data can be shifted
in or out of one of the split SAM registers, starting from any at the 256 TAP locations, excluding
the last address of each split SAM the data is shifted in or out sequentially starting from the
selected TAP location at the most significant bit (255 or 511) of the first split SAM, and then the
SAM pointer moves to the TAP location selected for the second split SAM to shift data in or out
sequentially, starts from this TAP location at the most significant bit (511 or 255), and finally
wraps around to the least significant bit.
TAP
0
1
2
TAP
255
256 257
511
32/37
¡ Semiconductor
MSM548262
DATA TRANSFER OPERATIONS
Upper SAM
256 ¥ 8
Array
Serial Decoder
Upper SAM
256 ¥ 8
256 ¥ 256 ¥ 8
Memory
256 ¥ 256 ¥ 8
Memory
Array
Lower SAM
256 ¥ 8
256 ¥ 256 ¥ 8
Memory
Array
Lower SAM
256 ¥ 8
The MSM548262 features two types of bidirectional data transfer capability between RAM and
SAM.
1) Conventional (non split) transfer: 512 words by 8 bits of data can be loaded from RAM to SAM
(Read transfer), or from SAM to RAM (Write transfer).
2) Split transfer: 256 words by 8 bits of data can be loaded from the lower/upper half of the RAM
to the lower/upper half of the SAM (Split read transfer), or from the lower/upper half of SAM
to the lower/upper half of RAM (Split write transfer).
The conventional transfer and split transfer modes are controlled by the DSF input signal.
Data transfer are invoked by holding the TRG signal "low" at the falling edge of RAS.
The MSM548262 supports 4 types of transfer operations: Read transfer, Split read transfer, Write
transfer and Split write transfer as shown in the truth table. The type of transfer operation is
determined by the state of CAS, WE and DSF latched at the falling edge of RAS. During
conventional transfer operations, the SAM port is switched from input to output mode (Read
transfer), or output to input mode (Write transfer). It remains unchanged during split transfer
operation (Split read transfer or Split write transfer).
Both RAM and SAM are divided by the most significant row address (AX8), as shown in Figure
1. Therefore, no data transfer between AX8 = 0 side RAM and AX8 = 1 side RAM can be provided
through the SAM. Care must be taken if the split read transfer on AX8 = 1 side (or AX8 = 0 side)
is provided after the read transfer or the split read transfer, is provided on AX8 = 0 side (or AX8
= 1 side).
256 ¥ 256 ¥ 8
Memory
AX8 = 0
Array
AX8 = 1
SAM I/O Buffer
SDQ1 - 8
Figure 1. RAM and SAM Configuration
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MSM548262
Read Transfer: RAS falling edge --- CAS = WE = "H", TRG = DSF = "L"
Read transfer consists of loading a selected row of data from the RAM into the SAM register. A
read transfer is invoked by holding CAS "high", TRG "low", WE "high", and DSF "low" at the
falling edge of RAS. The row address selected at the falling edge of RAS determines the RAM row
to be transferred into the SAM. The transfer cycle is completed at the rising edge of TRG. When
the transfer is completed, the SAM port is set into the output mode. In a read/real time read
transfer cycle, the transfer of a new row of data is completed at the rising edge of TRG, and this
data becomes valid on the SDQ lines after the specified access time tSCA from the rising edge of
the subsequent SC cycles. The start address of the serial pointer of the SAM is determined by the
column address selected at the falling edge of CAS. In a read transfer cycle (which is preceded
by a write transfer cycle), SC clock must be held at a constant VIL or VIH after the SC high time
has been satisfied. A rising edge of the SC clock must not occur until after the specified delay tTSD
from the rising edge of TRG.
In a real time read transfer cycle (which is preceded by another read transfer cycle), the previous
row data appears on the SQD lines until the TRG signal goes "high", and the serial access time
tSCA for the following serial clock is satisfied. This feature allows for the first bit of the new row
of data to appear on the serial output as soon as the last bit of the previous row has been strobed
without any timing loss. To make this continuous data flow possible, the rising edge of TRG must
be synchronized with RAS, CAS, and the subsequent rising edge of SC (tRTH, tCTH, and tTSL/tTSD
must be satisfied).
Masked Write Transfer: RAS falling edge --- CAS = "H", TRG = WE = DSF = "L"
Write transfer cycle consists of loading the content of the SAM register into a selected row of the
RAM. This write transfer is the same as a mask write operation in RAM.
If the SAM data to be transferred must first be loaded through the SAM, a Masked write transfer
operation (all DQ pins "low" at falling edge of RAS) must precede the write transfer cycles. A
masked write transfer is invoked by holding CAS "high", TRG "low", WE "low" and DSF "low"
at the falling edge of RAS. The row address selected at the falling edge of RAS determines the
RAM row address into which the data will be transferred. The column address selected at the
falling edge of CAS determines the start address of the serial pointer of the SAM. After the write
transfer is completed, the SDQ lines are set in the input mode so that serial data synchronized
with the SC clock can be loaded.
When consecutive write transfer operations are performed, new data must not be written into
the serial register until the RAS cycle of the preceding write transfer is completed. Consequently,
the SC clock must be held at a constant VIL or VIH during the RAS cycle. A rising edge of the SC
clock is only allowed after the specified delay tCSD from the falling edge of the CAS, at which time
a new row of data can be written in the serial register.
Data transferred to SAM by read transfer cycle or split read transfer cycle can be written to the
other address of RAM by write transfer cycle. However, the address to write data must be the
same as that of the read transfer cycle (row address AX8).
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MSM548262
Split Data Transfer and QSF
The MSM548262 features a bidirectional split data transfer capability between the RAM and
SAM. During split data transfer operation, the serial register is split into two halves which can
be controlled independently. Split read or split write transfer operation can be performed to or
from one half of the serial register, while serial data can be shifted into or out of the other half of
the serial register. The most significant column address location (A8C) is controlled internally to
determines which half of the serial register will be reloaded from the RAM. QSF is an output
which indicates which half of the serial register is in an active state. QSF changes state when the
last SC clock is applied to active split SAM.
Split Read Transfer: RAS falling edge --- CAS = WE = DSF = "H", TRG = "L"
Split read transfer consists of loading 256 words by 8 bits of data from a selected row of the split
RAM into the corresponding non-active split SAM register. Serial data can be shifted out from
the other half of the split SAM register simultaneously. During split read transfer operation, the
RAM port input clocks do not have to be synchronized with the serial clock SC, thus eliminating
timing restrictions as in the case of real time read transfers. A split read transfer can be performed
after a delay of tSTS from the change of state of the QSF output is satisfied.
Conventional (non-split) read transfer operation must precede split read transfer cycles.
Masked Split Write Transfer: RAS falling edge --- CAS = DSF = "H", TRG = WE ="L"
Split write transfer consists of loading 256 words by 8 bits of data from the non-active split SAM
register into a selected row of the corresponding split RAM. Serial data can be shifted into the
other half of the split SAM register simultaneously. During split write transfer operation, the
RAM port input clocks do not have to be synchronized with the serial clock SC, thus allowing
for real time transfer. This write transfer operation, which is the same as a mask write operation
in RAM, can be selectively controlled for 8 DQis by inputing the mask data from DQ1 - DQ8 at
the falling edge of RAS.
A split write transfer can be performed after a delay of tSTS from the change of state of the QSF
output is satisfied.
A masked write transfer operation must precede split write transfer. The purpose is to switch the
SAM port from output mode to input mode, and to set the initial TAP location prior to split write
transfer operations.
POWER UP
Power must be applied to the RAS and TRG input signals to pull them "high" before, or at the
same time as, the VCC supply is turned on. After power-up, a pause of 200 ms minimum is
required with RAS and TRG held "high". After the pause, a minimum of 8 RAS and 8 SC dummy
cycles must be performed to stabilize the internal circuitry, before valid read, write or transfer
operations can begin. During the initialization period, the TRG signal must be held "high". If the
internal refresh counter is used, a minimum 8 CAS before RAS cycles are required instead of 8
RAS cycles.
(NOTE) INITIAL STATE AFTER POWER UP
The initial state can not be guaranteed for various power up conditions and input signal levels.
Therefore, it is recommended that the initial state be set after the initialization of the device is
performed and before valid operations begin.
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MSM548262
PACKAGE DIMENSIONS
(Unit : mm)
SOJ40-P-400-1.27
Mirror finish
Package material
Lead frame material
Pin treatment
Solder plate thickness
Package weight (g)
Epoxy resin
42 alloy
Solder plating
5 mm or more
1.70 TYP.
Notes for Mounting the Surface Mount Type Package
The SOP, QFP, TSOP, SOJ, QFJ (PLCC), SHP and BGA are surface mount type packages, which
are very susceptible to heat in reflow mounting and humidity absorbed in storage.
Therefore, before you perform reflow mounting, contact Oki’s responsible sales person for the
product name, package name, pin number, package code and desired mounting conditions
(reflow method, temperature and times).
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¡ Semiconductor
MSM548262
(Unit : mm)
TSOPII44/40-P-400-0.80-K
Mirror finish
Package material
Lead frame material
Pin treatment
Solder plate thickness
Package weight (g)
Epoxy resin
42 alloy
Solder plating
5 mm or more
0.49 TYP.
Notes for Mounting the Surface Mount Type Package
The SOP, QFP, TSOP, SOJ, QFJ (PLCC), SHP and BGA are surface mount type packages, which
are very susceptible to heat in reflow mounting and humidity absorbed in storage.
Therefore, before you perform reflow mounting, contact Oki’s responsible sales person for the
product name, package name, pin number, package code and desired mounting conditions
(reflow method, temperature and times).
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