psf21911 ETC-unknow, psf21911 Datasheet - Page 98

• Manufacturer Part Number: psf21911
• Description: Isdn Echocancellation Circuit Terminal Applications Iec-q
• Manufacturer: ETC-unknow

PSB 21911
PSF 21911
Monitor Channel Programming
3.2
Monitor Channel Programming
Important: This chapter applies only in µP mode.
The example on page 99 illustrates the read-out of the transceiver’s identification
number (ID). It consists of the transmission of a two-byte message from the control unit
to the transceiver in IOM channel 0. The transceiver acknowledges the receipt by
returning a two-byte long message in the monitor channel. The procedure is absolutely
identical for Monitor channel 1.
The P starts the transfer procedure after having confirmed that the monitor channel is
inactive. The first byte of monitor data is loaded into the transmit register MOX. Via the
Monitor Control Register MOCR monitor interrupts are enabled and control of the MX-bit
is handed over to the IEC-Q TE. Then transmission of the first byte begins. The U-
transceiver reacts to a low level of the MX-bit by reading and acknowledging the monitor
channel byte automatically. On detection of the confirmation, the IEC-Q TE issues a
monitor interrupt to inform the P that the next byte may be sent. Loading the second
byte into the transmit register results in an immediate transmission (timing is controlled
by IEC-Q TE). The U-transceiver receives the second byte in the same manner as
before. When transmission is completed, the U-transceiver sends “End of Message”
(MX-bit high).
It is assumed that a monitor command was sent that needs to be answered by the U-
transceiver (e.g. read-out of a register). Therefore, the U-transceiver commences to
issue a two-byte confirmation after an End-of-Message indication from the IEC-Q TE has
been detected. The IEC-Q TE notifies the P via interrupt when new monitor data has
been received. The processor may then read and acknowledge the byte at a convenient
instant. When confirmation has been completed, the U-transceiver sends “EOM”. This
generates a corresponding interrupt in the IEC-Q TE. By setting the MR-bit to high, the
monitor channel is inactive, the transmission is finished.
Semiconductor Group
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11.97