~ National ~ Semiconductor - Al Kossow's Bitsavers

7.0 CPU Registers (Continued)
ICR INTERRUPT CONTROL REGISTER
[Main R2; read/write]
RIS1,O -
Receiver Interrupt Select ... Defines the
source of the Receiver Interrupt.
RIS1,O Interrupt Source
00 RFF + RE
01 DAV + RE
1 0 (unused)
11 RA
"+ .. indicates logical "or".
7 6 5 4 3 2 1 0
I RIS1 I RISO I rsv I IM4 11M3 11M2 I IM1 liMO I
IM4-0 -Interrupt Mask ... Each bit, when set high,
masks an interrupt. 1M3 functions as an interrupt
mask only if BIRO is defined as an input. When
BIRO is defined as an output, 1M3 controls the
state of BIRO.
IM4-0
Interrupt
00000 No Mask
XXXX1 Receiver
XXX1X Transmitter
XX1XX Line Turn-Around
X1XXX Bi-Directional
1XXXX Timer
ISP INTERNAL STACK POINTER
[Main R30; read/write]
ASP3-0- Address Stack Pointer ... Input/output port of
the address stack pOinter. Further information:
Chapter CPU.
7 654 321 0
76543210
I TFE I RFF I LA I LTA I DEME I RAR I ACK I POLL I
DEME - Data Error or Message End ... In 3270 & 3299
modes, asserted when a byte parity error is detected.
In 5250 modes, asserted when the [111]
station address is decoded and [DAV] is asserted.
Cleared by reading I RTR}. Undefined in
8-bit modes and in the first frame of 3299
modes.
RAR - Received Auto-Response ... Set high when a
3270 Auto-Response message is decoded and
[RAR] is asserted. Cleared by reading I RTR I.
Undefined in 5250 and 8-bit modes and in the
first frame of 3299 modes.
ACK - Poll/ ACKnowledge ... Set high when a 3270
poll/ack command is decoded and [RAR] is asserted.
Cleared by reading I RTR}. Undefined in
5250 and 8-bit modes and in the first frame of
3299 modes.
POLL - POLL ... Set high when a 3270 poll command is
decoded and [RAR] is asserted. Cleared by
reading I RTR I. Undefined in 5250 and 8-bit
modes and in the first frame of 3299 modes.
RTR RECEIVE/TRANSMIT REGISTER
[Alternate R4; read/write]
RTF7-0- Receive Transmit FIFO's ... Input/output port
to the least significant eight bits of receive and
transmit FIFO's. [OWPl, [TF10-8] and
[RTF7 -0] are pushed onto the transmit FIFO on
moves into IRTR}. [RF10-8] and [RTF7-0]
are popped from receiver FIFO on moves out of
I RTR I. Further information: Transceivers.
7 6 5 4 321 0
DSP3-0- Data Stack POinter ... Input/output port of the
data stack pointer. Further information: Chapter
CPU.
NCF NETWORK COMMAND FLAG REGISTER
[Main R1; read only]
TFE - Transmit FIFO Empty ... Set high when the
FIFO is empty. Cleared by writing to I RTR}.
RFF - Receive FIFO Full ... Set high when the Receive
FI FO contains 3 received words. Cleared
by reading to I RTR}.
LA - Line Active ... Indicates activity on the receiver
input. Set high on any transition; cleared after
detecting no input transitions for 16 TCLK periods.
LTA - Line Turn Around ... Set high when end of
message is received. Cleared by writing to
I RTR I writing a "1" to this location, or by asserting
[TRES].
rsv. . state is undefined at all times
TCR TRANSCEIVER COMMAND REGISTER
[Alternate R6; read/write]
RLO - Receive Line Quiesce ... Selects number of
line quiesce bits the receiver looks for.
SEC
SLR
Number of
RLQ
Quiesces
o 2
1 3
- Select Error Codes ... When high {ECR I is
switched into {RTR I location.
- Select Line Receiver ... Selects the receiver
input source.
SLR Source
o TTL-IN
1 On-chip analog
line receiver
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