PEB 20560
Description of Registers
Semiconductor Group
5-71
2003-08
XPR
Each interrupt source can be selectively masked by setting the respective bit in the
MASK_A/B-register (bit position corresponding to the ISTA_A/B-register). Masked
interrupts are internally stored but not indicated when reading ISTA_A/B and also not
flagged into the top level ISTA. After releasing the respective MASK_A/B-bit they will be
indicated again in ISTA_A/B and in the top level ISTA.
When writing register MASK_A/B while ISTA_A/B indicates a non masked interrupt the
INT-pin is temporarily set into the inactive state. In this case the interrupt remains
indicated in the ISTA_A/B until these registers are read.
enables(0)/disables(1) the Transmit Pool Ready interrupt.
5.1.1.6.5
Extended Interrupt Register (EXIR_A/B)
Access: read
Reset value: 00
H
XMR
Transmit Message Repeat.
The transmission of a frame has to be repeated because:
– A frame consisting of more then 32 bytes is polled a second time in
auto-mode.
– Collision has occurred after sending the 32nd data byte of a message in
a bus configuration.
– CTS (transmission enable) has been withdrawn after sending the 32nd
data byte of a message in point-to-point configuration.
Transmission Data Underrun/Extended transmission End.
The actual frame has been aborted with IDLE, because the XFIFO holds no
further data, but the frame is not yet complete according to registers
XBCH/XBCL. In extended transparent mode, this bit indicates the
transmission end condition.
It is not possible to transmit frames when a XMR- or XDU-interrupt is indicated.
EHC
Extended HDLC-frame.
The SACCO has received a frame in auto-mode which is neither a RR- nor
an I-frame. The control byte is stored temporarily in the RHCR-register but
not in the RFIFO.
RFO
Receive Frame Overflow.
A frame could not be stored due to the occupied RFIFO (i.e. whole frame has
been lost). This interrupt can be used for statistical purposes and indicates,
that the CPU does not respond quickly enough to an incoming RPF- or RME-
interrupt.
XDU/EXE
bit 7
bit 0
XMR
XDU/EXE
EHC
RFO
0
RFS
0
0