Motorola MPC8260 User Manual

29-58

MOTOROLA

29.10.2.3.6  ABR Protocol-SpeciÞc TCTE
Figure 29-36 shows the ABR protocol-speciÞc TCTE. 

Table 29-27 describes ABR-speciÞc TCTE Þelds. 

0

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

Offset + 0x00

ER-TA

Offset + 0x02

CCR-TA

Offset + 0x04

MCR-TA

Offset + 0x06

TUAR

Ñ

CI-TA NI-TA

Ñ

CP-TA

Ñ

CI-VC

Ñ

Offset + 0x08

MCR

Offset + 0x0A

UNACK

Offset + 0x0C

ACR

Offset + 0x0E

ACRC

Ñ

Offset + 0x10

RM Cell Time Stamp (RCTS)

Offset + 0x12

Offset + 0x14

FRST

Ñ

CDF

COUNT

Offset + 0x16

ICR

Offset + 0x18

CRM

Offset + 0x1A

ADTF

Offset + 0x1C

ER

Offset + 0x1E

ER-BRM

0x00

Ñ

ER-TA

Explicit rateÐturn-around cell. Holds the ER of the last received F-RM cell. If another F-RM 
cell arrives before the previous F-RM cell was turned around, this Þeld is overwritten by the 
new RM cellÕs ER.

0x02

Ñ

CCR-TA Current cell rateÐturn-around cell. Holds the CCR of the last received F-RM cell. If another 

F-RM cell arrives before the previous F-RM cell was turned around, this Þeld is overwritten 
by the new RM cellÕs CCR.

0x04

Ñ

MCR-TA Minimum cell rateÐturn-around cell. Holds the MCR of the last received F-RM cell. If 

another F-RM cell arrives before the previous F-RM cell is turned around, this Þeld is 
overwritten by the new RM cellÕs MCR.

0x06

0

TUAR

Turn-around ßag. The CP sets TUAR to indicate that a new F-RM cell was received, which 
causes the transmitter to send a B-RM cell whenever the ABR ßow control permits. 
Initialize to 0.

1

Ñ

Reserved, should be cleared.

2

CI-TA

Congestion indicationÐturn-around cell. Holds the CI of the last received F-RM cell. If 
another F-RM cell arrives before the previous F-RM cell was turned around, CI-TA is 
overwritten by the new RM cellÕs CI.

3

NI-TA

No increaseÐturn-around cell. Holds the NI of the last received F-RM cell. If another F-RM 
cell arrives before the previous one was turned around, NI-TA is overwritten by the new 
RM cellÕs NI.