s6b0724 Densitron Corporation, s6b0724 Datasheet - Page 21

• Manufacturer Part Number: s6b0724
• Description: 132 Seg / 65 Com Driver & Controller For Stn Lcd
• Manufacturer: Densitron Corporation

S6B0724
Busy Flag
The Busy Flag indicates whether the S6B0724 is operating or not. When DB7 is "H" in read status operation, this
device is in busy status and will accept only read status instruction. If the cycle time is correct, the microprocessor
needs not to check this flag before each instruction, which improves the MPU performance.
Data Transfer
The S6B 0724 uses bus holder and internal data bus for data transfer with the MPU. When writing data from the MPU
to on-chip RAM, data is automatically transferred from the bus holder to the RAM as shown in figure 4. And when
reading data from on-chip RAM to the MPU, the data for the initial read cycle is stored in the bus holder (dummy
read) and the MPU reads this stored data from bus holder for the next data read cycle as shown in figure 5. This
means that a dummy read cycle must be inserted between each pair of address sets when a sequence of address
sets is executed. Therefore, the data of the specified address cannot be output with the read display data instruction
right after the address sets, but can be output at the second read of data.
CS1B
SCLK
CS2
SID
RS
COLUMN ADDRESS
PRELIMINARY SPEC. VER. 1.1
BUS HOLDER
DB0 to DB7
MPU signals
Internal signals
/ W RB
/ W RB
RS
DB7
DB6
Figure 5. Serial Interface Timing
N
N
Figure 6. Write Timing
DB5
N
DB4
D(N)
D(N)
132 SEG / 65 COM DRIVER & CONTROLLER FOR STN LCD
DB3
N+1
D(N+1)
D(N+1)
DB2
DB1
N+2
D(N+2)
D(N+2)
DB0
N+3
D(N+3)
D(N+3)
DB7
DB6
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