W925E240 Datasheet, PDF (51/73 Pages) Winbond – 8-BIT CID MICROCONTROLLER

W925E/C240
Fs
1
DIVA
(DIVC.0)
DIVS
(CKCON1.1)
overflow
13 14
Executing DIV Int
Clear by software
D
Q
ck
CR
DIVF
(EXIF.3)
Figure 6-13 13/14-bit Divider
6.15 Calling Identity Delivery (CID)
W925E/C240 provides type I and type II of CID system. Type I is on-hook calling with CID message
and type II is off-hook call on waiting. The CID function includes FSK decoder, dual tone alert signal
detector, ring detector and DTMF receiver. The FSK demodulation function can demodulate Bell 202
and ITU-T V.23 Frequency Shift keying (FSK) with 1200-baud rate. The Tone Alert Signal detect
function can detect dual tones of Bellcore Customer Premises Equipment(CPE) Tone Alerting
Signal(CAS) and BT Idle State and Loop State Tone Alert Signal. The line reversal for BT, ring burst
for CCA or ring signal for Bellcore can be detected by ring detector. It is compatible with Bellcore TR-
NWT-000030 & ST-TSV-002476, British Telecom(BT) SIN227, U.K. Cable Communications
Association(CCA) specification. The DTMF receiver can be programmed as DTMF decoder to decode
16 DTMF signals or tone detector to detect the signal which frequency is in DTMF band. The tone
detector can be an auxiliary detector to improve the performance of detecting tone-alerting
signal(CAS), said as talk down-off, in type II system.
The FSK decoder, alert tone detector and DTMF receiver can be enable/disable individually by the bits
of FSKE, CASE and DTMFE in FSK DATA REGISTER(FSKDR). CIDE is the global control bit to
enable/disable FSK decoder, alert tone detector and DTMF receiver. However, the ring detector is
always active.
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Publication Release Date: July 12, 2005
Revision A10