LV25200M_10 Datasheet, PDF (42/45 Pages) Sanyo Semicon Device – Single chip Tuner IC for Car Radio

LV25200M
Composition of The General-Purpose Counter
The general-purpose counter consists of 20-bit binary counters.
The count result can be read from MSB through the DO pin.
General-purpose counter
(20-bit binary counter)
HCTR
CTS
1
2
(FIF)
L
S
B
0 to 3
4 to 7
8 to 11
12 to 15
M
S
B
16 to 19
DO pin
CTE
4/8/32/64ms
GT
C=FIF × GT
GT1, GT0
On the basis of GT0 and GT1 data, the measurement time for frequency measurement using the general-purpose
counter can be selected from four types: 4,8,32,64 ms. By determining how many pulses are entered in the general-
purpose counter within one of these periods, the frequency of signal entered in HCTR in IC can be determined.
CTP data: Data to determine the general-purpose counter input pin (HCTR) state at reset of this counter (CTE=0)
CTP = 0: General-purpose counter input pin turned OFF (pulled down)
= 1: General-purpose counter input pin not pulled down, but the wait time reduced to 1- 2 ms.
When setting CTP=1, it must be set first not later than 4 ms before count start (CTE=1).
When the counter is not to be used, set CTP=0.
Frequency measurement mode
GT1
GT0
Measurement time
CTP=0
Wait time
CTP=1
0
0
0
1
1
0
1
1
4ms
8ms
32ms
64ms
3 to 4ms
7 to 8ms
1 to 2ms
IF Counter Operation
Before count start with the general-purpose counter, set CTE=0 to reset the counter beforehand.
The general-purpose counter starts counting by setting the serial data to CTE=1.
Then, the count result of the counter must be read out while CTE=1.
(With CTE=0, the general-purpose counter is reset.)
The signal entered in the HCTR pin in IC is divided into one half internally, and transmitted to the general-purpose
counter.
Accordingly, the count result of general-purpose counter is the one-half value of the actual frequency entered in the
HCTR pin in IC.
CE
Frquency measurement time
CTE=1
data
Wait time
Measurement time
HCTR
Input signal
No.A0976-42/45