
5 REGISTERS
SID13705 HARDWARE FUNCTIONAL
EPSON
C-1-17
SPECIFICATION
Figure 5-1 Screen-Register Relationship
Consider an example where REG[13h], REG[12] = 0CEh for a 320
×240 display sys-
tem. The upper 207 lines (CEh + 1) of the panel show an image from the Screen 1 Start
Word Address. The remaining 33 lines show an image from the Screen 2 Start Word
Address.
bits 7-0
LUT Address Bits [7:0]
These 8 bits control a pointer into the Look-Up Tables (LUT). The SID13705 block has
three 256-position, 4-bit wide LUTs, one for each of red, green, and blue – refer to Sec-
tion 8 “LOOK-UP TABLE ARCHITECTURE” on page C-1-23 for details.
This register selects which LUT entry is read/write accessible through the LUT Data
Register (REG[17h]). Writing the LUT Address Register automatically sets the pointer
to the Red LUT. Accesses to the LUT Data Register automatically increment the
pointer.
For example, writing a value 03h into the LUT Address Register sets the pointer to
R[3]. A subsequent access to the LUT Data Register accesses R[3] and moves the
pointer onto G[3]. Subsequent accesses to the LUT Data Register move the pointer onto
B[3], R[4], G[4], B[4], R[5], etc.
Note: The RGB data is inserted into the LUT after the Blue data is written, i.e. all three
colors must be written before the LUT is updated.
REG[15h] Look-Up Table Address Register
Address = 0x039FFF5
Read/Write
LUT Address
Bit 7
LUT Address
Bit 6
LUT Address
Bit 5
LUT Address
Bit 4
LUT Address
Bit 3
LUT Address
Bit 2
LUT Address
Bit 1
LUT Address
Bit 0
Line 0
Line 1
(REG[0Dh], REG[0Ch]) Words
Line 0 Last Pixel Address + REG[11h] Words
Line 0 Last Pixel Address=((REG[0Dh], REG[0Ch]) +
(8(REG[04h]+1)
× BPP/16))
8(REG[04h]+1) Pixels
Virtual Image
REG[11h] Words
Line=(REG[13h], REG[12h])
((REG[06h], REG[05])+1) Lines
Image 1
Image 2
(REG[0Fh], REG[0Eh]) Words
Where:
(REG[0Dh], REG[0Ch]) is the Screen 1 Start Word Address
BPP is Bits-per-Pixel as set by REG[02h] bits 7:6
REG[11h] is the Address Pitch Adjustment in Words
(REG[0Fh], REG[0Eh]) is the Screen 2 Start Word Address
(REG[13h], REG[12h]) is the Screen 1 Vertical Size
(REG[06h], REG[05h]) is the Vertical Panel Size
Words