
Data Sheet
613
Rev. 1.2, 2006-01-26
QuadFALCTM
PEF 22554 E
T1/J1 Registers
Interrupt Status Register 1
All bits are reset when ISR1 is read. If bit GCR.VIS is set, interrupt statuses in ISR1 are flagged although they are
masked by register IMR1. However, these masked interrupt statuses neither generate a signal on INT (or INT1,
ISR1_T
Offset
Reset Value
Interrupt Status Register 1
xx69H
00H
Field
Bits
Type
Description
CASE
7
r
Transmit CAS Register Empty
In ESF format this bit is set with the beginning of a transmitted multiframe
related to the internal transmitter timing. In F12 and F72 format this
interrupt occurs every 24 frames to inform the user that new bit robbing
data may be written to the XS(12:1) registers. This interrupt is generated
only if the serial signaling access on the system highway is not enabled.
RDO
6
r
Receive Data Overflow - HDLC Channel 1
This interrupt status indicates that the external micro controller did not
respond fast enough to an RPF or RME interrupt and that data in RFIFO
has been lost. Even when this interrupt status is generated, the frame
continues to be received when space in the RFIFO is available again.
Note: Whereas the bit RSIS.RDO in the frame status byte indicates
whether an overflow occurred when receiving the frame currently
accessed in the RFIFO, the ISR1.RDO interrupt status is generated
as soon as an overflow occurs and does not necessarily pertain to
the frame currently accessed by the processor.
ALLS
5
r
All Sent - HDLC Channel 1
This bit is set if the last bit of the current frame has been sent completely
and XFIFO is empty. This bit is valid in HDLC mode only.
XDU
4
r
Transmit Data Underrun - HDLC Channel 1
Transmitted frame was terminated with an abort sequence because no
data was available for transmission in XFIFO and no XME was issued.
Note: Transmitter and XFIFO are reset and deactivated if this condition
occurs. They are reactivated not before this interrupt status register
has been read. Thus, XDU should not be masked by register IMR1.
Additionally, CMDR.SRES must be set after XDU occurs to reset
the transmit signaling controller.
XMB
3
r
Transmit Multiframe Begin
This bit is set with the beginning of a transmitted multiframe related to the
internal transmit line interface timing.