WORD
NAME
DESCRIPTION
CT+14
SRIP
Shared Receive Descriptro Ring Index Pointer. This field contains the Index Pointer to the
CT entry with the CURRD and RDRA (CTADR+14, +16) to be used for received frames
rather than the CURRD & RDRA specified in the current CT entry, if SRIPE = 1. All 13
bits of this field will be used to index into the CT, regardless of DLCI1K setting in CSR2.
SRIPE(00)
SRIP Enable. When set, this bit enables the sharing of one Receive Descriptor Ring
by many DLCIs or CT entries. When SRIPE=1, the Receive Descriptor Ring and buffer
associated with the CURRD and RDRA values in the CT entry pointed to by the SRIP
Index Pointer will be used for the received frame rather than the CURRD and RDRA
values in the current CT entry associated with the DLCI of the received frame. The
RCCNT & XCCNT used will also be those in the CT entry pointed to by the SRIP.
CT+16
CURRD
(15:8)
Specifies the current receive descriptor in the ring (0 - 127 in the upper 7 bits). This field
should initially be written with zeroes.
CT+16,+18
RDRA
Starting address of the Receive Descriptor Ring for a channel. It must be word aligned.
CT+20
Rcv FECNs
Counter for keeping track of the FECNs received when a channel is ready.
Rcv BECNs
Counter for keeping track of the BECNs received when a channel is ready.
CT+22
Rcv DEs
Counter for keeping track of the DEs received when a channel is ready.
Discard
Frames
Counter for keeping track of received frames with DE = 1 that are discarded due to
congestion on a channel. Incremented for LMI frames is received on CT0 inconsistent
with the operating mode. (Stop or Re-Initialization will not reset this nor any CT Counter.)
CT+24
RCCNT
RX Congestion Counter. This counter is incremented each time a received frame is
placed into the RX descriptor Ring for that channel. The MK50H28 does this just prior to
clearing the OWNA bit(s) for the descriptor(s) corresponding to each received frame.
NOTE: This counter should be programmed with an initial value of 00. It is the
responsibility of the host processor to decrement and/or reset this counter as needed to
do Receive Descriptor Ring congestion monitoring
XCCNT
TX Congestion Counter. This counter is incremented each time a frame is transmitted
from the TX descriptor Ring for that channel. The MK50H28 does this just prior to clearing
the OWNA bit(s) for the descriptor(s) corresponding to each tranmitted frame.
NOTE: It is the responsibility of the host processor to program this counter with the 2’s
complement value of the number of descriptors that it filled with frame data to be
transmitted, if Transmit Descriptor Ring congestion monitoring is needed.
CT+26
RGF Cnt
Received Good Frames Counter. (Stop or Re-Init will not reset this nor any CT Counter.)
CT+28 - 31
0
Reserved. Must be written as zeros.
4.2.5 Interrupt Descriptor Ring Addresses
1
4
1
3
0
7
0
8
1
0
1
2
0
1
0
2
0
3
0
4
0
5
0
9
0
6
1
5
IADR + 24
IADR + 26
TINTADR <15:00>
0
TINTADR <23:16>
RESERVED
IADR + 28
IADR + 30
RINTADR <15:0 0>
0
RINTADR <23:16>
RESERVED
BIT
NAME
DESCRIPTION
15:08
0
Reserved, must be written as a zero.
07:00/15:00
TINTADR
Transmit Interrupt Descriptor Ring Address. (Must begin on a word boundary).
07:00/15:00
RINTADR
Receive Interrupt Descriptor Ring Address. (Must begin on a word boundary).
MK50H28
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