HT0324A Tomato LSI, Inc., HT0324A Datasheet - Page 18

• Manufacturer Part Number: HT0324A
• Description: 65COM / 132SEG DRIVER & CONTROLLER FOR STN LCD
• Manufacturer: Tomato LSI, Inc.

HT0324A
TOMATO LSI Inc.
f. Data accessing
The HT0324A uses bus holder and internal data bus for data read and data write with the MPU.
When writing data from the MPU to on-chip RAM, the data is automatically transferred from the bus
holder to the on-chip RAM as shown in figure 6-2. When the MPU reads data from on-chip RAM, the first
data read cycle stores the data 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 6-3. This means 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. Therefore, a dummy read cycle must be inserted between each pair of
address sets when a sequence of address sets is executed.
Address
Address
Column
Column
to DB0
to DB0
Holder
Holder
/WR
DB7
/WR
Bus
/WR
DB7
/WR
Bus
/RD
/RD
RS
RS
65COM / 132SEG DRIVER & CONTROLLER FOR STN LCD
18
N
N
N
N
N
N
D(N)
D(N)
Dummy
Figure 6-2. Write timing
Figure 6-3. Read timing
D(N)
N+1
N+1
D(N+1)
D(N+1)
D(N)
D(N+1)
N+2
N+2
D(N+2)
D(N+2)
D(N+1)
D(N+2)
N+3
N+3
D(N+3)
D(N+3)
D(N+2)
D(N+3)
N+4
Ver 0.0
N+4
D(N+4)
D(N+4)
D(N+3)
D(N+4)
N+5