MSM514262-10JS View Datasheet(PDF) - Oki Electric Industry
Part Name
Description
MFG CO.
'MSM514262-10JS' PDF : 45 Pages View PDF
¡ Semiconductor
MSM514262
DATA TRANSFER OPERATION
The MSM514262 features two types of bidirectional data transfer capability between RAM and
SAM, as shown in Figure 1 below.
1) Conventional (non split) transfer : 512 words by 4 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 4 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.
512 ¥ 512 ¥ 4
Memory
Array
512 ¥ 256 ¥ 4
Memory
Array
512 ¥ 256 ¥ 4
Memory
Array
512 ¥ 4
1) Conventional Transfer
Figure 1.
256 ¥ 4
256 ¥ 4
2) Split Transfer
The MSM514262 supports five types of transfer operation : Read transfer , Split read transfer,
Write transfer, Pseudo write transfer and Split write transfer as shown in truth table. Data
transfer are invoked by holding the DT/OE signal “low” at the falling edge of RAS. The type
of transfer operation is determined by the state of CAS, WB/WE, SE 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/Pseudo write transfer)
Whereas it remains unchanged during split transfer operation (Split read transfer or Split write
transfer).
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