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MSM6794

Display data register (DRAM)

D7

D6

D5

D4

D3

D2

D1

D0

8-bit DATA

—

6-bit DATA

This register is used to write or read display data to and from the liquid crystal display RAM. The

contents of this register are written or read to and from the address set by the X address register

and Y address register.

The bit length of display data is selected by the WLS bit (D6 bit) of the control register. If 6-bit

data is selected, writing to the D7 and D6 bit is invalid, and "0" is always read from these bits.

D7 (D5 for 6-bit DATA) is MSB, and D0 is LSB.

The content of this register does not change, even if the RESET pin is set to "L".

X address register (XAR)

D7

D6

D5

D4

D3

D2

D1

D0

—

XAD

This register is used to set the X address of the liquid crystal display RAM.

If 8-bit data is selected by the WLS bit (D6 bit) of the control register, the addresses are 0 to15 (00H

to 0FH). If 6-bit data is selected, the addresses are 0 to 21 (00H to 15H). If other addresses are set,

operation is unpredictable.

Writing to the D7 to D5 bits is invalid, and "0" is always read from these bits.

This register is reset to "0" by setting the RESET pin to "L".

Y address register (YAR)

D7

D6

D5

D4

D3

D2

D1

D0

—

YAD

This register is used to set the Y address of the liquid crystal display RAM.

If 1/48 duty is selected by DUTY bits (D1, D0 bits) of the control register, the address set value

is 0 to 47 (00H to 2FH). If 1/44 duty is selected, the address set value is 0 to 43 (00H to 2BH). If

1/41 duty is selected, the address set value is 0 to 40 (00H to 28H), and if 1/33 duty is selected,

the address set value is 0 to 32 (00H to 20H). If other values are set, operation is unpredictable.

Writing to D7 and D6 bits is invalid, and "0" is always read from these bits.

This register is reset to "0" by setting the RESET pin to "L".