PCA8514T PHILIPS [NXP Semiconductors], PCA8514T Datasheet - Page 14

• Manufacturer Part Number: PCA8514T
• Description: Stand-alone OSD
• Manufacturer: PHILIPS [NXP Semiconductors]

Philips Semiconductors
8.2
Three registers are used to address and load data into the
display RAM. These registers are described below.
8.2.1
Table 5 DCR Address Register
This register holds the address of the location in display
RAM into which data is to be written. Command 3 loads
the High nibble of the address into this register;
Command 4 loads the Low nibble of the address.
8.2.2
Table 6 DCR Attribute Register
The Attribute Register is loaded with character font
attribute data using Command 2. The data will be loaded
into bits <4-0> of the location in RAM addressed by the
contents of DCRAR. Bits 7 to 5 are not used and are
reserved.
8.2.3
Table 7 DCR Character Register
This register holds the character font data loaded by
Command 5. The data will be loaded into bits <12-5> of
the location in RAM addressed by the contents of DCRAR.
1995 Nov 27
A7
Stand-alone OSD
7
7
7
Loading character data into display RAM
DCR A
DCR A
DCR C
A6
C6
6
6
6
DDRESS
TTRIBUTE
HARACTER
A5
C5
5
5
5
A4
C4
T4
R
4
4
4
R
EGISTER
R
EGISTER
EGISTER
C3
A3
T3
3
3
3
(DCRAR)
(DCRTR)
(DCRCR)
C2
A2
T2
2
2
2
A1
C1
T1
1
1
1
A0
C0
T0
0
0
0
14
8.3
The procedure for writing character data to the display
RAM is as follows:
1. Select the start address in display RAM. The start
2. Load the character attributes into DCRTR using
3. Load the Character Font data into DCTCR using
A description of all the Commands is given in Chapter 9.
address can take any value between 0 and 255.
Command 3 is used to load the High nibble of the start
address. Command 4 is used to load the Low nibble of
the start address. The start address is stored in
DCRAR.
Command 2. The actual attribute selected is
dependent upon whether the Character Font Code,
Carriage Return Code or Space Code has been
selected by Command 5 (see Section 8.1).
If the attributes of a series of displayed characters are
the same, the contents of this register need not be
updated.
Command 5. This command signals that a complete
command byte is available and the data held in
registers DCRTR and DCRCR is loaded into the RAM
location pointed to by the address stored in DCRAR.
The address held in DCRAR is then incremented by ‘1’
pointing to the next RAM location in anticipation of the
next operation.
Writing character data to display RAM
Product specification
PCA8514