hsp50210 Intersil Corporation, hsp50210 Datasheet - Page 27

• Manufacturer Part Number: hsp50210
• Description: Digital Costas Loop
• Manufacturer: Intersil Corporation

A different read procedure is required depending on
whether the Lock Detector Accumulators, loop filter
accumulators, or the Status Register is to be read. The
read procedures are summarized in Figures 21 - 23.
The accumulators in the AGC Loop Filter, Carrier Loop
Filter and Symbol Tracking Loop can be read via the
Microprocessor Interface. Since these accumulators are
free running, their contents must be loaded into output
holding registers before they can be read. Each
accumulator has its own output holding register. The three
holding registers are updated by loading 29 (decimal) into
the Write Address Register of the Microprocessor Interface.
The output of a particular holding register is then enabled
for reading by loading its address into the Read Address
Register (see Tables 13 and 14). The holding register
addresses for the loop filter accumulators range from 0 to 4
as given in Table 12. The contents of the output holding
registers are multiplexed out a byte at a time on C7-0 by
changing A2-0 and asserting RD (see Read/Write Address
Map in Table 11).
REGISTERS
Total = 16
(4)
(4)
(1)
(2)
(2)
(2)
(1)
#
32-Bit Carrier Loop Letter Lag Acc. Output
32-Bit Symbol Tracking Loop Letter Lag Acc. Output
8-Bit AGC Loop Letter Output
16-Bit Lock Detector e Acc. Output
16-Bit Lock Detector GE Acc. Output
16-Bit Lock Detector FL/FE Acc. Output
8-Bit Internal Status
3-27
DEFINITION
HSP50210
The contents of the three accumulators in the Lock Detector
can also be read via the Microprocessor Interface. However,
the Lock Detector must be stopped before a read can be
performed. In State Machine Control Mode, the Lock
Detector is stopped by loading 24 (decimal) into the Write
Address Register. In Microprocessor Control Mode, the Lock
Detector stops after each Integration Period. To determine
when the Lock Detector has stopped and is ready for
reading, bits 7 and 6 of the Internal Status Register (SR7&6)
must be monitored (see Table 15). The control sequence for
reading a Lock Detector Accumulator is shown in Figure 22.
The control sequence for reading a Lock Detector
Accumulator using the LKINT signal is shown in Figure 23.
An 8-bit Internal Status Register (SR7-0) can also be
monitored via the Microprocessor interface. The Status
Register indicates loop filter and Lock Detector status as
listed in Table 13. The Status Register contents are output
on C7-0 by setting A2-0 to 100 (binary) an asserting RD as
shown in Figure 24. The register contents are updated
each CLK.
ADDRESS
0
1
2
3
4
TABLE 12. READ ENABLE ADDRESS MAP
Carrier Loop Filter Lag Accumulator. Enables output
of holding register containing 32 MSBs of the lag
accumulator.
Symbol Tracking Loop Filter Lag Accumulator.
Enables output of holding register containing 32
MSBs of the lag accumulator.
AGC GAIN. Enables output of holding register
containing 8 MSBs of the AGC accumulator.
Lock Detector 1. The 16 MSBs of the Lock
Detector’s Phase Error Accumulator and the 16
MSB’s of the False Lock Accumulator are enabled
for output. The accumulator contents are selected
for output as follows, A2-0 = 3 (decimal) selects
MSByte of the Phase Error Accumulator, A2-0 = 2
(decimal) selects LSByte of the Phase Error
Accumulator, A2-0 = 1 (decimal) selects MSByte of
the False Lock Accumulator, and A2-0 = 0 (decimal)
selects LSByte of the False Lock Accumulator.
Lock Detector 2. Enables the 16 MSBs of the Lock
Detector’s Gain Error Accumulator for output. The
MSByte of the accumulator is selected for output by
setting A2-0 = 1, and the LSByte is selected by
A2-0 = 0.
HOLDING REGISTER ENABLE