
Device Operation
 (Continued)
pendent of the video data clock,
 VCLK
. Inputs
 AD[9:0]
,
RD/WR
 and
 ANC/CTRL
 have internal pull down devices.
ACLK
 does not have an internal pull down device.
Control Data Read Functions
Control data
 is input to and output from the CLC030 using
the lower-order 8 bits
 AD[7:0]
 of the Ancilliary/Control Data
Port. This control data initializes, monitors and controls op-
eration of the CLC030. The upper two bits
 AD[9:8]
 of the
port function as handshaking signals with the device access-
ing the port.
 AD[9:8]
 must be driven as 00b (0XXh, where
XX are AD[7:0]) when either a control register read or write
address is being written to the port.
 AD[9:8]
 must be driven
as 11b (3XXh, where XX are AD[7:0]) when control data is
being written to the port. When control data is being read
from the port, the CLC030 will output
 AD[9:8]
 as 10b (2XXh,
where XX are output data AD[7:0]) and may be ignored by
the monitoring system.
Note:
 When power is first applied to the device or after it is
reset, the
 Ancilliary and Control Data Port
 must be initial-
ized to receive data. This is done by toggling
 ACLK
 three (3)
times.
Figure 1shows the sequence of clock and control signals for
reading control data from the ancilliary/control data port.
Control data read mode
 is invoked by making the
ANC/CTRL
 input low and the
 RD/WR
 input high. The 8-bit
address of the control register set to be accessed is input to
the port on bits
 AD[7:0]
. The address is captured on the
rising edge of
 ACLK
. When a control register read address
is being written to the port,
 AD[9:8]
 must be driven as 00b
(0XXh, where XX are AD[7:0]). When control data is being
read from the port, the CLC030 will output
 AD[9:8]
 as 10b
(2XXh, where XX are output data AD[7:0]) and may be
ignored by the monitoring system. Data being output from
the selected register is driven by the port immediately follow-
ing the rising edge of
 ACLK
 or when the address signals are
removed. For optimum system timing, the address signals
driving the port should be removed immediately after the
address is clocked into the device and before or coincident
with the falling edge of
 ACLK
 at the end of the address
cycle. Output data remains stable until the next rising edge
of
 ACLK
 and may be read by external devices at any time
after the removal of the address signal. This second clock
resets the port from drive to receive mode and readies the
port for another access cycle.
Example:
 Read the Full-field Flags via the AD port.
1.
Set
 ANC/CTRL
 to a logic-low.
2.
Set
 RD/WR
 to a logic-high.
3.
Present 001h to
 AD[9:0]
 as the register address.
4.
Toggle
 ACLK
.
5.
Release the bus driving the AD port.
6.
Read the data present on the AD port. The Full-field
Flags are bits AD[4:0].
7.
Toggle
 ACLK
 to release the AD port.
Control Data Write Functions
Figure 2shows the sequence of clock and control signals for
writing control data to the ancilliary/control data port. The
control data write mode
 is similar to the read mode. Con-
trol data write mode is invoked by making the
 ANC/CTRL
input low and the
 RD/WR
 input low. The 8-bit address of the
control register set to be accessed is input to the port on bits
AD[7:0]
. The address is captured on the rising edge of
ACLK
. The address data is removed after being clocked into
the device or before the falling edge of
 ACLK
. Next, the
control data is presented to the port bits
 AD[7:0]
 and written
into the selected register on the next rising edge of
 ACLK
.
When a control register write address is being written to the
port,
 AD[9:8]
 must be driven as 00b (0XXh, where XX are
AD[7:0]). When control data is being written to the port,
AD[9:8]
 must be driven as 11b (3XXh, where XX are
AD[7:0]). Control data written into the registers may be read
out non-destructively in most cases.
Example:
 Setup (without enabling) the TPG Mode via the
AD port using the 1125 line, 30 frame, 74.25MHz, interlaced
component (SMPTE 274M) colour bars as test pattern. The
TPG may be enabled after setup using the Multi-function I/O
port or by the control registers.
1.
Set
 ANC/CTRL
 to a logic-low.
2.
Set
 RD/WR
 to a logic-low.
3.
Present 00Dh to
 AD[9:0]
 as the Test 0 register address.
4.
Toggle
 ACLK
.
5.
Present 027h to
 AD[9:0]
 as the register data.
6.
Toggle
 ACLK
.
C
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