ml6461 Micro Electronics Corporation, ml6461 Datasheet - Page 24

• Manufacturer Part Number: ml6461
• Description: Ntsc Video Encoder
• Manufacturer: Micro Electronics Corporation

ML6461
FUNCTIONAL DESCRIPTION
PRESET PIN CONTROL
The ML6461 can be controlled by a pair of preset mode
pins. These pins do not allow access to all of the
programmable features of the ML6461, but are intended to
provide a simpler interface for most applications. Refer to
Table 8 for preset modes.
SERIAL BUS OPERATION
The serial bus control in the ML6461 has two levels of
addressing: Device Addressing and Functional Addressing.
Device Addressing: Figures 15, 16, and 17 show the
physical waveforms generated in order to address the
ML6461. There are six basic parts of the waveform:
1. Start Indication: Clock Cycle 0
2. Device Address Shifted in: Clock Cycle 1 through 8
3. Device Address Strobed and Decoded: Clock Cycle 9
4. Function Address Shifted in: Clock Cycle 10 through 17
5. Function Address Strobed and Decoded: Clock Cycle 18
6. Data Shifted in 8 bits at a time, MSB first: Clock
Cycle 19 through 26
7. Data Shifted: Clock Cycle 27
8. Repeat strep 6 & 7 until all data is clocked in.
9. Stop indication: After Last Clock Cycle
Note: data at SDATA is ignored at steps 3, 5, and 7.
Device & Function Addressing: Figures 15, 16, an17
show the register address procedure of the ML6461.
X = don't care
Mode Description
Mode A: All register contents are programmed through serial interface.
Mode B: Master mode, CCIR656 rate, analog blanking.
Mode C: Slave mode, SAV and EAV codes, CCIR656 rate, digital blanking.
Mode D: Slave mode, external sync at start of line, Square pixel rate, analog blanking
24
(54 for CC, 54 for CNTR)
MODE
D
A
B
C
PRESET1
0
0
1
1
Table 8. Preset Modes and Register Values
(Continued)
PRESET0
0
1
0
1
Device Address (8 bit)
1011 0100 (Hex = B4)
Function Address (8 bit)
Closed Caption Data Registers (CC): 0000 0000 (Hex = 00)
Control Registers (CNTR): 0000 0011 (Hex = 03)
Number of Data Bits
Closed Caption Data Registers (CC): 4 x 8 bits
Control Registers (CNTR): 4 x 8 bits
CONTROL REGISTER DEFAULT SETTINGS
At Power up, the ML6461 default settings are as follows:
To get black at power up will require logic “1” in A30.
Control Register is undefined when the serial
bus mode is enabled.
Chip is ready to process video
Preset Pins are available and if used will
configure the control register.
Must write logic “0” (zero) to A30 to get
video
CC
XX
XX
XX
XX
XXXXXXXX
1C080209
09080209
11080209
CNTR