THS8083APZPG4 Datasheet, PDF (54/63 Pages) Texas Instruments – Triple 8-Bit, 80 MSPS 3.3-V Video and Graphics

Examples:
1. For generating the XGA@75Hz pixel clock of 78.75 MHz, with F(XTL) = 14.381818 MHz and
VCODIV=8:
NOM_INC = [32x14.31818x8]/[78.75x2] = 23.272724...
Since 23d = 17h and INT(0.272724… x 2^27) = 36604438d = 22E8A16 hex, this can be written as
0x17.22E8A16 or as a contiguous 33 bit number: 010111010001011101000101000010110 = 0BA2E8A16
hex, i.e., the default setting for NOM_INC (see register map).
To achieve lock with an incoming HS, TERMCNT is programmed with 1312 (i.e., the total number of pixels
per line in this mode).
Below are the settings for popular video and graphics modes.
VESA MODES
Mode #1: 640x350 at 85 Hz → fpix = 31.5 MHz, N = 832
REGISTER NAME
TERM_CNT_0
TERM_CNT_1
NOM_INC_0
NOM_INC_1
NOM_INC_2
NOM_INC_3
NOM_INC_4
VCO_DIV
SEL_CLK
VALUE
(DEC)
832
VALUE
(HEX)
340
29.090905 1d.0ba2c9c
8
8
4
4
REGISTER VALUE
(HEX)
40
03
9c
2c
ba
e8
0
3
2
Mode #2: 640x400 at 85 Hz → fpix = 31.5 MHz, N = 832 (same settings as 640x350 at 85 Hz)
Mode #3: 720x400 at 85 Hz → fpix = 35.5 MHz, N = 936
REGISTER NAME
TERM_CNT_0
TERM_CNT_1
NOM_INC_0
NOM_INC_1
NOM_INC_2
NOM_INC_3
NOM_INC_4
VCO_DIV
SEL_CLK
VALUE
(DEC)
936
VALUE
(HEX)
3a8
25.813057 19.68123fa
8
8
4
4
REGISTER VALUE
(HEX)
a8
03
fa
23
81
ce
0
03
02
A−2