Page 22

Epson Research and Development

 

Vancouver Design Center

 

 

4.2.2 Gray Shade Modes

Gray shade modes are monochrome display modes. Monochrome display modes use the Look-Up Table in a very similar fashion to the color modes. This most significant difference is that the monochrome display modes use only the intensity of the green element of the Look-Up Table to form the gray level.

One side effect of using only green for intensity selection is that in gray shade modes there are only sixteen possible intensities. 8 bit-per-pixel is not supported for gray shade modes.

1 bpp gray shade

When the S1D13705 is configured for 1 bpp gray shade mode, the LUT is limited to selecting colors from the first two green entries. The two LUT entries can be set to any of sixteen possible intensities. Typically they would be set to 0h (black) and Fh (white).

Each byte in the display buffer contains eight adjacent pixels. If a bit has a value of “0” then the color in the green LUT 0 index is displayed. A bit value of “1” results in the color in green LUT 1 index being displayed.

The following table shows the recommended values 1 bpp gray shade display mode.

Table 4-5: Recommended LUT Values for 1 Bpp Gray Shade

Address

Red

Green

Blue

 

 

 

 

00

00

00

00

01

00

F0

00

02

00

00

00

...

00

00

00

FF

00

00

00

 

 

 

 

unused entries

2 bpp gray shade

When the S1D13705 is configured for 2 bpp gray shade, the displayed colors are selected from the first four green entries in the Look-Up Table. The remaining entries of the LUT are unused. Each of the four entries can be set to any of the sixteen possible colors.

Each byte in the display buffer contains four adjacent pixels. If a bit combination has a value of “00” then the intensity in the green LUT index 0 is displayed. A bit value of “01” results in the intensity represented by the green in LUT index 1 being displayed. Likewise the bit combination of “10” displays from the third LUT entry and “11” displays a from the fourth LUT entry.

S1D13705

Programming Notes and Examples

X27A-G-002-03

Issue Date: 02/01/22

Page 116
Image 116
Epson S1D13705 technical manual Gray Shade Modes, Recommended LUT Values for 1 Bpp Gray Shade, Address Red Green Blue