Kawasaki 80C152 - Manual (Page 108)

KS152JB Universal Communications Controller
Technical Specifications
Kawasaki LSI USA, Inc. Page 108 of 120 Ver. 0.9 KS152JB2
GREN has no effect on whether the receiver detects a collision in CSMA/CD mode as the receiver
input circuitry always monitors the receive pin.
RSTAT.2 (RFNE) - Receive FIFO Not Empty - If set, indicates that the receive FIFO contains data.
The receive FIFO is a three byte buffer into which the receive data is loaded. A CPU read of the
FIFO retrieves the oldest data and automatically updates the FIFO pointers. Setting GREN to a one
will clear the receive FIFO. The status of this flag is controlled by the GSC. This bit is cleared if
the user software empties receive FIFO.
RSTAT.3 (RDN) - Receive Done - If set, indicates the successful completion of a receiver opera-
tion. Will not ne set is a CRC, alignment, abort or FIFO overrun error occurred.
RSTAT.4 (CRCE) - CRC Error - If set, indicates that a properly aligned frame was received with a
mismatched CRC.
RSTAT.5 (AE) - Alignment Error - In CSMA/CD mode, AE is set if the receiver shift register (an
internal serial-to-parallel converter) is not full and CRC is bad when an EOF is detected. In CSMA/
CD the EOF is a line idle condition (see LNI) for two bit times. If the CRC is correct while in
CSMA/CD mode, AE bit is not set and any mis-alignment us assumed to be caused by dribble bits
as the line went idle. in SDLC mode. AE is set if a non-byte-aligned flag is received. CRC may also
be set. The setting of this flag is controlled by the GSC.
RSTAT.6 (RCABT) - Receiver Collision/Abort Detect - If set, indicates a collision was detected
after data had been loaded into the receive FIFO in CSMA/CD mode. In SDLC mode, RCABT
indicates that 7 consecutive 1’s were detected prior to the end of flag but after data has been loaded
into the receive FIFO. AE may also be set if RCABT is set.
RSTAT.7 (OVR) - Overrun - If set, indicates that the receive FIFO was full and new shift register
data was written into it. It is cleared by the user software. AE and/or CRCE may also be set if OVR
is set.
SARH0 (0A3H) - Source Address Register High 0, contains the high byte of the source address for
the DMA Channel 0.
SARH1 (0B3H) - Source Address Register High 1, contains the high byte of the source address for
the DMA Channel 1.
SARL0 (0A2H) - Source Address Register Low 0, contains the low byte of the source address for
the DMA Channel 0.
SARL1 (0B2H) - Source Address Register Low 1, contains the low byte of the source address for
the DMA Channel 1.
SAS - Source Address Space bit, see DCON0.
SBUF (099H) - Serial Buffer, both the receive and transmit SFR location for the LSC.