UPD17073 NEC, UPD17073 Datasheet - Page 152

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

16.4 Using IF Counter
and count error.
16.4.1 Using hardware of IF counter
component of the input signal with a capacitor C.
and the voltage applied to the pin is about 1/2V
consequently, the IF counter does not function normally.
until counting is started.
recommended to use the function with the SD (Station Detection) output, and so on, of the tuner.
152
External frequency
The following sections 16.4.1 through 16.4.3 describe how to use the hardware of the IF counter, program example,
Figure 16-8 shows the block diagram when the P0D2/AMIFC pin and P0D3/FMIFC/AMIFC pins are used.
Table 16-1 shows the range of frequency that can be input to the P0D2/AMIFC pin and P0D3/FMIFC/AMIFC pin.
As shown in Figure 16-8, the input pin of the IF counter is provided with an AC amplifier; therefore, cut off the DC
When the P0D2/AMIFC or P0D3/FMIFC/AMIFC pin is selected for the IF counter function, switch SW turns ON
If the intermediate voltage does not rise sufficiently at this time, the AC amplifier is not in the normal operating range;
Therefore, provide a sufficient wait time after each pin has been specified to be used for the IF counter function,
When using the IF counter function for the auto tuning function of a radio to detect broadcasting stations, it is
Figure 16-8. Block Diagram of IF Count Function of Each Pin
P0D3/FMIFC/AMIFC
FMIF mode
P0D3/FMIFC/AMIFC
AMIF mode
P0D2/AMIFC
AMIF mode
Table 16-1. IF Counter Input Frequency Range
Input pin
C
FMIFC
AMIFC
DD
.
10 - 11
0.4 - 2
0.4 - 0.5
0.4 - 2
0.4 - 0.5
Input frequency
(MHz)
R
0.1
0.15
0.1
0.15
0.1
Input amplitude
(V
P-P
)
SW
PD17072,17073
To internal counter