
KS152JB Universal Communications Controller Technical Specifications
RDN from being set.
CRCE
AE
RCABT
OVR
GREN
EOF RECEIVED
GSCRE
Clear
GREN
Set
RDN
Receive Error Flag (Logic for Clearing GREN, Setting RDN)
A CRC Error means the CRC generator did not come to its correct value after calculating the CRC of the message plus received CRC. An alignment error means the number of bits received between the BOF and EOF was not a multiple of 8.
In SDLC mode, the CRC bit gets set at the end of any frame in which there is a CRC error, and the AE bit gets set at the end of any frame in which there is an Alignment Error.
In CSMA/CD mode, if there is no CRC Error, neither CRCE nor AE will get set. If there is a CRC error and no Alignment Error, the CRCE bit will get set, but not the AE bit. If there is both a CRC Error and an Alignment Error, then the AE bit will get set, but not the CRCE bit. Thus in CSMA/ CD mode, the CRCE and AE bits are mutually exclusive.
The Receive Abort flag, RCABT, gets set if an incoming frame was interrupted after received data had already passed to the Receive FIFO. In the SDLC mode, this can happen if a line idle condi- tion is detected before an EOF flag is. In CSMA/CD mode, this can happen if there is a collision. In either case, the CPU will have to
The Overrun Error flag, OVR, gets set if the GSC Receiver is ready to push a newly received byte onto the Receive FIFO, but the FIFO is full.
Up to 7 “dribble bits” can be received after the EOF without causing an error condition.
6.0 GLOSSARY
ADR0,1,2,3 (95H, 0A5H, 0B5H, 0C5H) - Address Match Registers 0, 1, 2, 3 - The contents of these SFR’s are compared against the address bits from the serial data on the GSC. If the address matches the SFR, then the C152 accepts that frame. If in 8 bit addressing mode a match with any of the four registers will trigger acceptance. In the 16 bit addressing mode, a match with ADR1:ADR0 or ADR3:ADR2 will be accepted. Address length is determined by GMOD (AL).
AE - Alignment Error, see RSTAT.
Kawasaki LSI USA, Inc. | Page 98 of 120 | Ver. 0.9 KS152JB2 |