83C795 Datasheet, PDF (44/136 Pages) List of Unclassifed Manufacturers – Ethernet System Controller

ETHERNET SYSTEM CONTROLLER REGISTERS
83C795
5.2.21 RCNTH - Receive Byte Count High
Register
Normal Map R ead Port = 0:1B
T his regis ter contains theupper 8 bits of thereceive
unit’s count of bytes received in the mos t recent
frame. It is cleared by the receive unit at the s tart of
reception.
BIT
7 CT15
6 CT14
5 CT13
4 CT12
3 CT11
2 CT10
1 CT09
0 CT08
RCNTH
RESET
0
0
0
0
0
0
0
0
5.2.22 RCNTL - Receive Byte Count Low
Register
Normal Map R ead Port = 0:1A
T his regis ter contains the lower 8 bits of the receive
unit’s count of bytes received in the mos t recent
frame. It is cleared by the receive unit at the s tart of
reception.
BIT
7 CT07
6 CT06
5 CT05
4 CT04
3 CT03
2 CT02
1 CT01
0 CT00
RCNTL
RESET
0
0
0
0
0
0
0
0
5.2.23 RCON - Receive Configuration
Register
Normal Map R ead Port = 2:1C Normal Map Write
Port = 0:1C
Linked-List MapR eadPort = 2:1C Linked-List Map
Write Port = 0:1C
T he R eceive Configuration R egis ter defines
optional behavior of the receive unit. It controls
addres s recognition and the acceptance of
abnor mal packets . T hes e bits can be s et
independently, although the monitor mode takes
precedence over the other bits .
BIT
RCON
70
6 RCA
5 MON
4 PROM
3 GROUP
2 BROAD
1 RUNTS
0 SEP
RESET
0
0
0
0
0
0
0
0
Bit 7: Unused
T his bit is unus ed in 83C795. When read, it always
returns zero.
Bit 6: RCA, Receive Abort Frame on Collision
S etting this bit allows the receiver unit to abort
reception of any frame in which the COL pin is
active after the s tart of frame delimiter. R eception
of any frame whos e prefix contains cons ecutive ’0’
bits is also aborted. Neither cause res ults in R XE
being s et. It is not overridden by the S E P bit. T his
bit was unused in the 83C690.
Bit 5: MON, Check Addresses/CRC Without
Buffering
MON = 1 - T his bit enables thereceiveunit tocheck
address es and CR C on incoming packets without
buffering them to memory. T he Mis s ed Packet
Counter (MPCNT ) will be incremented for each
recognized packet.
MON = 0 - T his is normal operation.
Bit 4: PROM, Promiscuous Reception
When PR OM = 1, this bit enables promiscuous
reception of all frames havingindividual addres ses .
31