EM65570
68COM/ 98SEG 65K Color STN LCD Driver
7.3.2 Register Read Operation
The EM65570 can read the control registers. When issuing a control register read
operation, the upper data bus nibble (D7-D4) is used for the register address (0 to FH).
Up to 16 registers can be accessed directly. However, more than 16 registers are
provided. To solve this over supply problem, the EM65570 uses the register bank
control to access the RE register with a bank number. You can access the RE register
through any bank. The following lists the steps to be taken when accessing the specific
register using the bank access control.
1. Set 01H to RE register for access to the RA register.
2. Set the specific register address to the RA register.
3. Set the specific register bank to the RE register.
4. Read the contents at the specific register.
WRB
01H
addr
bank
Bank number
write to RE
data
read specific
register
D0~D7
Bank number write Address write
to RE for RA to RA
RDB
RS
Figure 7-6 Register Read Operation
7.4 16-Bit Data Access to Display RAM
The EM65570 has both 8-bit and 16-bit data bus sizes. The data bus size can be
selected by the WLS register.
WLS = “0”: 8-bits bus size
WLS = “1”: 16-bits bus size
In 16-bit access mode, the Control Register Access uses the low-byte data bus
(D7~D0) in the internal circuit and does not use the high-byte data bus (D15~D8).
When reading control register using 16-bit bus, data exist at D3~D0 while D15~D4 is
always 1 or “H”.
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Product Specification (V1.0) 09.05.2005
(This specification is subject to change without further notice)
ELAN [ ELAN MICROELECTRONICS CORP ]
