saa6703ah NXP Semiconductors, saa6703ah Datasheet - Page 65

• Manufacturer Part Number: saa6703ah
• Description: Xga Analog Input Flat Panel Controller.
• Manufacturer: NXP Semiconductors

Philips Semiconductors
The multicolour font definitions have to start always from
address 0 and the start of the single colour definitions is
indicated by the configurable single colour start code
(OSDT_SC register). This means all the characters with
charcodes below the OSDT_SC value are treated as
multicolour and all charcodes above this value are handled
as single colour characters. To use only multicolour
characters in the RAM font set this value must be set to an
unreachable value. Due to the RAM size of 4 kbyte a
multicolour 8
256 characters as maximum so it is enough to set only
bit 8 in OSDT_SC_HI register to logic 1. To use only single
colour definitions set the complete OSDT_SC pointer
simply to 000H.
A character is stored in the font RAM using the
OSDT_CC_HI, OSDT_CC_LO, OSDT_CMASK and
OSDT_CDEF registers where OSDT_CC gives the
charcode of the character to be defined and OSDT_CDEF
and OSDT_CMASK are used for the data bits and the
according mask using 8 bits at a time.
Table 45 Examples of possible font RAM configurations
2004 Apr 01
FONT SIZE
XGA analog input flat panel controller
12
24
32
12
9
8
13
8
16
18
24
32
single colour only
multicolour only
mixed example
single colour only
multicolour only
mixed example
single colour only
multicolour only
mixed example
single colour only
multicolour only
mixed example
single colour only
multicolour only
mixed example
single colour only
multicolour only
mixed example
8 font with 2 bits per pixel can hold
COLOUR
STORABLE CHARACTERS
65
The data format written to OSDT_CDEF has to be MSB
aligned representing the following pixel of the character
with the pixel sequence processed from top to bottom and
left to right. As mentioned before, a single colour pixel is
represented with one bit while a multicolour pixel needs
two bits to be described. So each definition of a character
will need multiple writes to OSDT_CDEF (8 bits at a time)
until the whole character is completed. The total number of
bytes to be transmitted is depending on the defined font
size and if the character uses a single or multicolour
definition.
512
256
256 single colour and 128 multicolour
170
85
100 single colour and 35 multicolour
151
75
121 single colour and 15 multicolour
280
140
200 single colour and 40 multicolour
56
28
40 single colour and 8 multicolour
32
16
24 single colour and 4 multicolour
MAXIMUM NUMBER
SAA6703AH
Product specification