Epson S1D13705 technical manual Registers, Examples, REG11h Memory Address Offset Register

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5.1.1 Registers

REG[11h] Memory Address Offset Register

Memory	Memory	Memory	Memory	Memory	Memory	Memory	Memory
Address	Address	Address	Address	Address	Address	Address	Address
Offset	Offset	Offset	Offset	Offset	Offset	Offset	Offset
Bit 7	Bit 6	Bit 5	Bit 4	Bit 3	Bit 2	Bit 1	Bit 0

Memory Address Offset Register

REG[11h] forms an 8-bit value called the Memory Address Offset. This offset is the number of additional words on each line of the display. If the offset is set to zero there is no virtual width.

Note

This value does not represent the number of words to be shown on the display. The dis- play width is set in the Horizontal Display Width register.

5.1.2 Examples

Example 1: In this example we go through the calculations to display a 640x480 im- age on a 320x240 panel at 2 bpp.

Step 1: Calculate the number of pixels per word for this color depth.

At 2 bpp each byte is comprised of 4 pixels, therefore each word contains 8 pixels.

pixels_per_word = 16 / bpp = 16 / 2 = 8

Step 2: Calculate the Memory Address Offset register value

We require a total of 640 pixels. The horizontal display register will account for 320 pixels, this leaves 320 pixels for the Memory Address Offset register to account for.

offset = pixels / pixels_per_word = 320 / 8 = 40 = 28h

The Memory Address Offset register, REG[11h], will have to be set to 28h to satisfy the above condition.

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