2–16
Table 2–6. Multiplex Mode and Bus-Width Selection (Continued)
MODE
SUB-
MODE
MULTIPLEX-
CONTROL
REGISTER 1
(HEX)
MULTIPLEX-
CONTROL
REGISTER 2
(HEX)
DATA
BITS
PER
PIXEL
(see
Note 8)
PIXEL-
BUS
WIDTH
MULTI-
PLEX
RATIO
(see
Note 9)
OVERLAY
BITS
PER
PIXEL
TABLE
REFERENCE
(see
Note 10)
Direct
1
06
1B
24
32
1
8
d1
24-bit
07
1B
24
32
1
8
d3
2
(5–6–5)
XGA
05
02
16
16
1
NA
d5
05
03
16
32
2
NA
d6
3
(5–5–5)
TARGA
04
02
15
16
1
1
d8
04
03
15
32
2
1
d9
4
16-bit
(6–6–4)
03
02
16
16
1
NA
d11
03
03
16
32
2
NA
d12
5
12-bit
(4–4–4)
9. Data bits per pixel is the number of bits of pixel port information used as color data for each displayed pixel,
often referred to as the number of bit planes.
10. Multiplex ratio indicates the number of pixels per bus load or the number of pixels associated with each
LCLK (load clock) pulse. For example, with a 32-bit pixel bus width and 8 bit planes, each bus load consists
of four pixels. In a typical implementation, the LCLK signal is either connected to or derived from RCLK.
Therefore, the RCLK divide ratio must be chosen as a function of the multiplex mode selected. The RCLK
divide ratio is not automatically set by mode selection but must be programmed in the output clock selection
register by the user.
11. This column is a reference to Tables 2–8 through 2–11, where the actual manipulation of pixel information
and pixel latching sequences are illustrated for each of the multiplexing modes.
12. It is recommended that all unused input terminals be connected to ground to conserve power.
13. Multiplex-control register 2 bit 7 enables (logic 1) and disables (logic 0 ) the VGA port. If auxiliary-window
or port-select switching is to be done involving the VGA port, this bit needs to be set to a logic 1 as well as
programming for the correct direct-color mode. For example, if auxiliary windowing is to be done with
direct-color submode 1 (32-bit pixel bus) and VGA, instead of programming 1B (hex), multiplex-control
register 2 should be programmed to 9B (hex). If only VGA pass-through is desired, the values should be
programmed for VGA mode as indicated in Table 2–6. If only VGA pass-through is desired, the values
should be programmed as indicated in Table 2–6 for VGA mode.
01
12
12
16
1
4
d14
01
13
12
32
2
4
d15
NOTES: