Kawasaki 80C152 - Manual (Page 111)

KS152JB Universal Communications Controller
Technical Specifications
Kawasaki LSI USA, Inc. Page 111 of 120 Ver. 0.9 KS152JB2
TMOD7 (GATE) - Gating Mode bit for Timer 1.
TSTAT (0D8H) - Transmit Status Register
TSTAT.0 (DMA) - DMA Select - If set, indicates that DMA channels are used to service the GSC
FIFO’s and GSC interrupts occur on TDN and RDN, and also enables UR to become set. If cleared,
indicates that the GSC is operating in it normal mode and interrupt occur on TFNE and RFNE. For
more information on DMA servicing please refer to DMA section on DMA serial demand mode
(4.2.2.3).
TSTAT.1 (TEN) - Transmit Enable - When set, causes TDN, UR, TCDT and NOACK flags to be
reset and TFIFO cleared. The transmitter will clear TEN after a successful transmission, a collision
during the data, CRC, or end flag. If cleared during transmission the GSC transmit pin goes to a
steady state high level. This is the method used to send an abort character in SDLC. Also DEN is
forced to high level. The end of transmission occurs whenever the TFIFO is emptied.
TSTAT.2 (TFNF) - Transmit FIFO Not Full - When set, indicates that the new data may be written
into the transmit FIFO. The transmit FIFO is a three byte buffer that loads the transmit shift register
with data.
TSTAT.3 (TDN) - Transmit Done - When set, indicates the successful completion of a frame trans-
mission. If HBAEN is set, TDN will not be set until the end of the IFS following the transmitted
message, so that the acknowledgment can be checked. If an acknowledgment is nor expected fol-
lowing a broadcast or multi-cast packet.
TSTAT.4 (TCDT) - Transmit Collision Detect- If set, indicates that the transmitter halted due to
collision. It is set if a collision occurs during the data or CRC or is there are more than eighth col-
lisions.
TSTAT.5 (UR) - Underruns - If set, indicates that in the DMA mode last bit was shifted out of the
transmit register and the DMA byte count did not equal zero. When an underrun occurs, the trans-
mitter halts without sending the CRC or the end flag.
TSTAT.6 (NOACK) - No Acknowledge - If set, indicates that no acknowledgment was received for
the previous frame. Will be set only if HBAEN is set and no acknowledge is received prior to the
end of the IFS. NOACK is not set following a broadcast or multicast packet.
TSTAT.7 (LNI) - Line Idle - If set, indicates that the receive line is idle. In SDLC protocol it is set
if 15 consecutive ones are received. In CSMA/CD protocol, line idle is set if GRxD remains high
for approximately 1.6 bit times. LNI is cleared after a transition on GSxD.
TxD - External Clock input for GSC transmitter.
0 1 2 3 4 5 6 7
TCDT TDN TFNF TEN DMA UR NOACK LNI