Register Description
4.1.9
Extended Interrupt Register
EXIR
Read
Address 24
H
Value after reset: 00
H
7
0
XMR
XDU
PCE
RFO
SOV
MOS
SAW WOV
XMR
XDU
Transmit Message Repeat
The transmission of the last frame has to be repeated because:
– the ISAC-S has received a negative acknowledgement to an I-frame in auto-mode
(according to HDLC/LAPD)
– or a collision on the S-bus has been detected after the 32nd data byte of a transmit
frame.
Transmit Data Underrun
The current transmission of a frame is aborted by transmitting seven "1's" because
the XFIFO holds no further data. This interrupt occurs whenever the processor has
failed to respond to an XPR interrupt (ISTA register) quickly enough, after having
initiated a transmission and the message to be transmitted is not yet complete.
Note: When an XMR or and XDU interrupt is generated, it is not possible to send
transparent frames or I-frames until the interrupt has been acknowledged by reading
EXIR.
PCE
Protocol Error
Used in auto-mode only.
A protocol error has been detected in auto-mode due to a received
– S- or I-frame with an incorrect sequence number N(R) or
– S-frame containing an I-field.
– I-frame which is not a command.
– S-frame with an undefined control field.
Receive Frame Overflow
RFO
The received data of a frame could not be stored, because the RFIFO is occupied.
The whole message is lost.
This interrupt can be used for statistical purposes and indicates that the processor
does not respond quickly enough to an RPF or RME interrupt (ISTA).
SOV
MOS
Synchronous Transfer Overflow
The synchronous transfer programmed in STCR has not been acknowledged in time
via the SC0/SC1 bit.
MONITOR Status
A change in the MONITOR Status Register (MOSR) has occured (IOM-2).
A new MONITOR channel byte is stored in MOR (IOM-1).
Semiconductor Group
209
INFINEON [ Infineon ]
