UPD17073 NEC, UPD17073 Datasheet - Page 144

• Manufacturer Part Number: UPD17073
• Description: 4-BIT SINGLE-CHIP MICROCONTROLLER WITH HARDWARE FOR DIGITAL TUNING SYSTEM
• Manufacturer: NEC

16. INTERMEDIATE FREQUENCY (IF) COUNTER
16.1 Outline of Intermediate Frequency (IF) Counter
output from a tuner.
4 ms, 8 ms, or open), by using a 16-bit counter.
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Remarks 1. IFCMD1 and IFCMD0 (bits 3 and 2 of IF counter mode select register. Refer to Figure 16-3) select
Figure 16-1 outlines the IF counter.
The IF counter is mainly used to detect broadcasting stations, and is used to count the intermediate frequency (IF)
The IF counter counts the frequency input to the P0D3/FMIFC/AMIFC or P0D2/AMIFC pin for a fixed time (1 ms,
P0D3/FMIFC/AMIFC
P0D2/AMIFC
2. IFCCK1 and IFCCK0 (bits 1 and 0 of IF counter mode select register. Refer to Figure 16-3) select
3. IFCSTRT (bit 1 of IF counter control register. Refer to Figure 16-5) controls starting of the IF counter.
4. IFCG (bit 0 of IF counter gate status detection register. Refer to Figure 16-6) detects opening/closing
5. IFCRES (bit 0 of IF counter control register. Refer to Figure 16-5) resets the count value of the IF
the IF counter function.
the gate time of the IF counter.
of the gate of the IF counter.
counter.
IF counter input
select block
Figure 16-1. Outline of Frequency Counter
IFCMD0 flag
IFCMD1 flag
IFCCK1 flag
IFCCK0 flag
control block
Gate time
IFCSTRT flag
control block
IFCG flag
Start
PD17072,17073
IFCRES flag
IF counter
(16 bits)
DBF