CMX867A Ver la hoja de datos (PDF) - CML Microsystems Plc
Número de pieza
componentes Descripción
Fabricante
CMX867A Datasheet PDF : 8 Pages
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Calling
Modem
(2)
Wait 456ms
N
Unscrambled 1s
still received ?
Y
Transmit Scrambled
1s at 1200b/s
Scrambled N
1s detected in high
band ?
Y
Scrambled N
1s in high band for
270ms ?
Y
Enable Rx USART
Load first data byte
to be transmitted
Wait 765ms
Start data
transmission
Error
Error
Wait for 456ms
Check Status ($E6) bit 6 to confirm that unscrambled 1s are
still being received.
Transmit Scrambled 1s at 1200b/s
Tx Mode ($E1)
b15..b12 = 1100 (select V.22 low band)
b6,b5 = 11 (scrambler and 64 x 1s detect enabled)
b4,b3 = 11 (select synchronous mode)
b2..b0 = 011 (select continous 1s)
Detect scrambled 1s in high band
Rx Mode ($E2)
b15..b12 = 1101 (select V.22 high band)
b7,b6 = 11 (descrambler and 64x1s detect enabled)
General Control ($E0)
b1 = 1 (unmask scrambled 1s IRQ)
b0 = 0 (mask IRQ)
Note that b0 was enabled earlier for 2225Hz Answertone
IRQ, but is disabled here after selecting V.22 high band because no
interrupt is yet required for Rx Data Overflow or Rx Data Ready.
On interrupt, check Status ($E6)
If b10 = 1 (Rx energy detected)
b8,b7 = 11 (scrambled 1s found)
Check scrambled 1s are detected for 270ms (nom.) If not then an
error has occured.
Enable Rx USART
NOTE The use of the autoequaliser can improve performance.
Rx Mode ($E2)
b8 = user defined (autoequaliser setting)
b5..b3 = user defined (Rx USART mode)
b2..b0 = user defined (data bits and parity
settings)
General Control ($E0)
b0 = 1 (unmask Rx Data overflow and Rx
Data Ready IRQ)
b1 = 0 (mask scrambled 1s detection IRQ)
Load Tx Data register ($E3 or $E4) with first byte
Note:- Check that Status ($E6) bit 12 = 1 (Tx Data Ready) before
loading the data.
Wait for 765ms
Start data transmission
Tx Mode ($E1)
b4,b3 = user defined (Tx USART settings)
b2..b0 = user defined (data and stop bit settings)
General Control ($E0)
b3 = 1 (unmask TX Data underflow and Tx
Data Ready IRQ)
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