EM65571AGH EMC [ELAN Microelectronics Corp], EM65571AGH Datasheet - Page 27

• Manufacturer Part Number: EM65571AGH
• Description: 130COM / 128SEG 65K Color STN LCD Driver
• Manufacturer: EMC [ELAN Microelectronics Corp]

Product Specification (V1.0) 08.04.2005
(This specification is subject to change without further notice)
7.4 16-Bit Data Access to Display RAM
7.5 Fast Burst RAM Write Function
The EM65571 corresponds to 8-bit and 16-bit bus size access.
The data bus size can be selected by the WLS register.
WLS = “0”: 8-bit bus size
WLS = “1”: 16-bit bus size
In the 16-bit access mode, in accessing the control register, use the low-byte data bus
(D7~D0). High byte data bus (D15~D8) are not used in internal circuits when reading
the control register using 16-bit bus. Register values are output to D3-D0 and D15-D4
output “H”.
The EM65571 has a built-in fast burst RAM write function. The burst mode transfers 32
bits of data in a block at once, so it can decrease half the access time needed for
common standard RAM write functions (16 bits data bus). The burst RAM write
function is suitable for frequently rewriting data such as displaying color animation.
operation, the data bus upper nibble (D7-D4) is used for register address (0 to FH).
A maximum of 16 registers can be accessed directly. Since there are more than 16
registers, the EM65571 has a register bank control. The RE register sets the bank
number to be accessed. And the RE address is 0FH, in any bank that can access
RE register, 4-steps are needed to read a specific register.
1. Write 04H to the RE register to access the RA register.
2. Write the specific register address to the RA register.
3. Write specific register bank to RE register.
4. Read specific register contents.
The EM65571 can read the control registers, in case of control register read
Register Read Operation
D0~D7
WRB
RDB
RS
Write the Bank number
to RE to access RA
04H
Figure 8. Register Read Operation
Address to RA
Write the
addr
130COM/128SEG 65K Color STN LCD Driver
Write the Bank
number to RE
bank
Read a Specific
data
Register
EM65571
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