Epson S1D13705 REG0Ch Screen 1 Start Word Address LSB, REG0Dh Screen 1 Start Word Address MSB

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7.4 Registers

This section describes the registers used to set portrait mode operation.

REG[0Ch] Screen 1 Start Word Address LSB

bit 7	bit 6	bit 5	bit 4	bit 3	bit 2	bit 1	bit 0
REG[0Dh] Screen 1 Start Word Address MSB
bit 15	bit 14	bit 13	bit 12	bit 11	bit 10	bit 9	bit 8
REG[0Eh] Screen 1 Start Word Address MSB
n/a	n/a	n/a	n/a	n/a	n/a	n/a	bit 16

The Screen 1 Start Address registers must be set correctly for portrait mode. In portrait mode the Start Address registers form a byte offset, as opposed to a word offset, into display memory.

The initial required offset is the portrait mode stride (in bytes) less one.

REG[1Ch] Line Byte Count Register

bit 7

bit 6

bit 5

bit 4

bit 3

bit 2

bit 1

bit 0

The line byte count register informs the S1D13705 of the stride, in bytes, between two consecutive lines of display in portrait mode. The Line Byte Count register only affects portrait mode operation and are ignored when the S1D13705 is in landscape display mode.

REG[1Bh] Portrait Mode Register

Portrait Mode	Portrait Mode				Portrait Mode	Portrait Mode	Portrait Mode
		n/a	n/a	n/a	Memory	Pixel Clock	Pixel Clock
Enable	Select
					Clock Select	Select Bit 1	Select Bit 0

The portrait mode register contains several items for portrait mode support.

The first is the Portrait Mode Enable bit. When this bit is “0” the S1D13705 is in landscape mode and the remainder of the settings in this register as well as the Line Byte Count in REG[1Ch] are ignored. Set this bit to “1” to enable portrait mode.

S1D13705	Programming Notes and Examples
X27A-G-002-03	Issue Date: 02/01/22