UPD161622 NEC, UPD161622 Datasheet - Page 20

• Manufacturer Part Number: UPD161622
• Description: 396 OUTPUT TFT-LCD SOURCE DRIVER
• Manufacturer: NEC

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5.1.5 Access to display data RAM and internal registers
can transfer data at high speeds. Usually, it is not necessary for the CPU to take wait time into consideration.
display data RAM. By using the high-speed write function, data can be written to the display RAM at an access speed
four times faster than that of the ordinary RAM write function. Therefore, applications, such as motion picture display
where the display data must be rewritten at high speeds, can be supported. For details, refer to 5.2.5 High-speed
RAM write mode
register (R12) cannot be read. This relationship is shown in Figure 5–6.
normal mode.
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When the CPU accessed the
A high-speed RAM write function, as well as the ordinary RAM write function, is provided for writing data to the
Dummy data is not required when either reading or writing data. In the
Note that when in write mode of data at high speed for data read mode of read cycle time, this mode equals to
Writing
Reading (display memory register)
Reading (registers other than display memory register)
DATA
DATA
/WR
/WR
/RD
/RD
DATA
/WR
IR Address
Set #n
IRn
n
Figure 5–6. Image of internal access to display RAM
n
PD161622, the CPU only has to satisfy the requirement of the cycle time (t
IRn Register
Data Sheet S15649EJ2V0DS
Data Read
Dummy
Data
IRn
n+1
IR Address
Set #n+1
n+2
n
n
PD161622, data of the display memory
IRn+1 Register
Data Read
n+3
n+1
n+1
PD161622
CYC
) and