cn8237 Mindspeed Technologies, cn8237 Datasheet - Page 281

• Manufacturer Part Number: cn8237
• Description: Atm Oc-12 Servicesar Plus With Xbr Traffic Management
• Manufacturer: Mindspeed Technologies

CN8237
ATM OC-12 ServiceSAR Plus with xBR Traffic Management
Figure 13-1. UTOPIA Level 2 Receive Timing
28237-DSH-001-C
(RXFLAG*)
(RXMARK)
RXADDR
RXCLAV
RXENB*
RXDATA
RXSOC
RXCLK
39
1F
40
4
in the CONFIG1 register. Polling is accomplished by outputting the desired port
number on the UTOPIA address bus. If that port has data ready, it asserts the
RxClav (RxFLAG*) line. The controller ignores this line and continues polling
other ports or it initiates the data transfer by holding the port address on the
address lines while RxEnb* is deasserted. Once the data transfer has begun, the
CN8237 continues polling other ports.
diagram assumes that eight ports are present. At clock cycle “a”, port 5 has just
been polled. It asserts the RxClav (RxFLAG*) line to indicate that it has a
complete cell to send. The CN8237 continues to poll ports 6 and 7 (both indicate
that they do not have cells at this time). During this entire polling operation, data
is being transferred across the data bus.
address bus but this time has raised the RxEnb* line. This selects port 5. Port 5
acknowledges that it is ready by again asserting RxClav (RxFLAG*). Port 5 then
asserts the RxSOC (RxMARK) line and begins to transfer data.
NOTE:
The CN8237 starts by polling port 0 and continues to NUM_PORTS as stored
The polling and selection process waveforms are shown in
At clock cycle “b”, the CN8237 has again output port 5 on the UTOPIA
1F
41
4
CN8237 does not poll on the transmit side.
Mindspeed Technologies
42
5
a
1F
43
5
44
6
1F
45
6
46
7
™
1F
47
7
b
48
5
13.0 ATM UTOPIA Interface
13.4 UTOPIA Level 2 Interface
1F
5
Figure
H1
0
13-1. This
1F
H2
8237_150
13-9