Z86129 Datasheet, PDF (23/50 Pages) Zilog, Inc. – NTSC LINE 21 DECIDER

PRELIMINARY
Z86129/130/131
NTSC Line 21 Decoder
the write of the READ1 or READ2 command. The data 3. SEN pin Low disabled the port, placing SDO in tri-
byte or bytes are then clocked-out in sequence, MSB first,
state. Signal transitions on SCK and SDA are ignored.
while NOP commands are written into the device. Data bits
are clocked-out on the rising edge of SCK. All available ^{4. SEN pin High enables the port for operation.}
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data bytes must be read to clear the DAV bit and permit
subsequent reads.
5. SEN and SMS pins Low is a hardware reset for the
part. These pins must be held Low for at least 100 ns.
The SPI Bus Protocol
1. The first bit of the first output byte is driven out on SDO
following the rising edge of SCK on the last bit (LSB)
of the READ1 or READ2 command.
6. Serial synchronization can be established by clocking
in the minimum required SSR string of FFh, FFh, FEh.
More than two bytes of FFh may be input but the string
must end with FEh.
2. Three-wire bus with Clock signal on SCK pin, Serial
Data Input on SDA pin and Serial Data Output on SDO
pin.
COMMANDS
Serial Port Commands
The majority of the Z86129/130/131 commands are
common to both the I²C and SPI modes. In the I²C mode,
the commands must be contained within the Start-Slave
Address-etc. sequence.
Note: In the following Command descriptions, the letter 'h'
following a command code designates Hexadecimal
notation.
Reset
RESET = FBh, FCh, 00h. RESET is a three byte
command sequence in SPI or I²C mode. The RESET
command will establish all the specified default settings in
the device, but it will not reset the serial port itself. This
sequence can be entered without RDY being set.
No Operation
NOP = 00h. NOP is a one-byte command for use in SPI or
I²C mode. The NOP command does not affect the status
of the RDY bit in the Serial Status (SS) register and can be
executed independent of the RDY status.
Serial Sync Bytes
SSB = FFh,....,FFh,FEh. Serial Sync Bytes are used in
SPI mode only. This command actually consists of a string
of single-byte commands in the form FFh,....FFh,FEh. SPI
mode communications can be synchronized by sending a
synchronizing data string to the part. This string should
consist of at least two SSB bytes of FFh followed by one
SSB byte of FEh. At the end of the FEh byte the port is
ready for use.
Table 8. Basic Serial Commands
Serial Command Command Code
RESET
FBh, FCh, 00h
NOP
00h
SSB
FFh,...FFh,FEh
Notes
SPI or I²C
SPI or I²C
SPI mode only
Caption/Text Display Mode Commands
CPTX = 10h-1Fh. Caption and Text display mode
commands. These commands select the desired Line 21
data stream (Closed Caption or Text) for display.
Bit CM7 CM6 CM5 CM4 CM3 CM2 CM1 CM0
0
0
0
1 FLD LANG CPTX DONOF
R/W R/W R/W R/W R/W R/W R/W R/W
Figure 12. CPTX-Caption/Text Display
(CPTX = 10h-1Fh)
Caption and Text display commands are one byte
commands. A data channel can be selected for display
with the display either enabled (DEC ON) or disabled
(DEC OFF). All these commands will turn off an active
XDS display mode. Table 9 summarizes the device’s
DS96TEL0200
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