FX613 Consumer Microcircuits Limited, FX613 Datasheet - Page 4

• Manufacturer Part Number: FX613
• Description: Universal Call Progress Decoder
• Manufacturer: Consumer Microcircuits Limited

Application Information ......
Principles of Decoder Operation
Level Detection
take place in parallel the audio signal should, under
normal circumstances, be input to both Signal In and
Level In pins via coupling capacitors.
preset ‘Must/Must Not Decode’ thresholds
(Specification Page), the Universal Call Progress
Decoder will be disabled.
Level In pin and attempt to decode under all
conditions, the decoder may be permanently enabled
by holding the Level In pin at V
The device can disabled by pulling Level In to V
Frequency Band Discrimination
crossing) inverting amplifier and then ‘filtered’ to
remove high-frequency noise and jitter.
determine the input frequency band (HI = 900Hz to
2150Hz, LO = 300Hz to 660Hz).
will operate as a LO Band decoder and will remain so
until a HI frequency signal is detected. If the input
frequency is in the HI Band, the device will operate as
a HI Band decoder and will remain so until a LO
frequency signal is detected.
band selection taking place every 9.8ms. It will
therefore take 9.8ms from Power-Up to set up the
initial correct decode frequency band.
On-Chip Timer Operation
the number of input cycles in a fixed time period. This
fixed period, measured by the continuous on-chip
timer, is set to 13.16ms for HI Band inputs and
39.47ms for LO Band inputs.
Level In
In Limits
Out of Limits
V
V
DD
SS
As level and frequency discrimination operations
If the input signal level (Level In) is outside the
If it is wished to disregard signal input levels at the
The input signal is amplified by a self-biased (zero-
High (HI) and Low (LO) counters are employed to
If the input frequency is in the LO Band, the device
Frequency band monitoring is continuous with the
For frequency measurement, the FX613 counts
Running/Reset
Running
Timer
Reset
Reset
DD
.
Enabled/Disabled
Disabled
Disabled
Enabled
IRQ
SS
.
4
N
µProcessor software timing as below.
On-Chip Timer Operation ......
When the timer expires the following actions take
place:
interrupt is reset.
reset in mid-count, and therefore unable to allow a
valid measurement, under the following conditions:
OTONE
a. Set the µP timer period to a period greater than
b. Each ‘Tone Measurement Complete’ interrupt
c. With N
a. A HI or LO (“1” or “0”) band indication bit is
b. The Frequency Counter count of 5-bits is latched
c. An interrupt is generated (IRQ) to the
a. A change of decode frequency band.
b. Decoder disabled; signal input level out of
c. Signal Quality Assessment considered ‘Bad’.
d. Input signal frequency outside limits.
The N
When the Chip Select input is set to “0” the
The On-Chip Timer and Frequency Counter will be
the relevant frequency-band measurement
period (13.16ms or 39.47ms).
from the FX613 must reset the µP timer.
the FX613 on-chip timer will be continually reset.
latched into Bit-5 of the Serial Output Port.
into the Serial Output Port (Bit-4 [MSB] to Bit-0).
The Serial Output Port Contains 6-bits, if 8 Serial
Clock edges are employed, two extra “0s”, which
should be ignored, will be output last.
µProcessor. The contents of the Serial Output
Port should be read before the next interrupt is
expected; if not data will be overwritten.
specification or Level Detect input set to V
ii
ii
Data Out
Disabled (frozen to previous bit-5 level
Enabled (dependent upon Quality measurement)
Disabled (frozen to previous bit-5 level)
Enabled
Recognition
will occur - the µP timer will run.
a N
No ‘Tone Measurement Complete’ interrupt
The µP Timer time-out can be considered as
OTONE
OTONE
OTONE
condition can be recognized using
or white noise at the decoder input,
indication.
SS
.