TTP/C-C2 Communication Controller – Preliminary Data Sheet

AS8202

Rev. 1.0, October 2000

Page 3 of 3

The CNI (communication network interface) forms a temporal firewall. It decouples the

controller network from the host subsystem by use of a dual ported RAM. This prevents the

propagation of control errors. The interface to the host CPU is implemented as 16 bit wide non-

multiplexed asynchronous bus interface.

TTP/C follows a conflict-free media access strategy called time-division-multiple access

(TDMA). This means, TTP/C deploys a time slot technique based on a global time which is

permanently synchronised. Each node is assigned a time slot in which it is allowed to perform

transmit operation. The sequence of time slots is called TDMA round, a set of TDMA rounds

forms a cluster cycle. After one cluster cycle the operation of the network repeats. The

sequence of interactions forming the cluster cycle is defined in a static time schedule, called

message-descriptor-list (MEDL). The definition of the MEDL in conjunction with the global time

determines the response time for a service request.

The membership of all nodes in the network is evaluated by the communication controller. This

information is presented in a consistent fashion to all correct cluster members. During

operation, the status of every other node is propagated within one TDMA round. The MEDL is

loaded into the configuration memory when the system starts up.

Package and Pin A ssignment

Type: TQFP 80, plastic package

test-se

AS8202

TTP/C

Communications

Controller

(TOP VIEW)

stest

resetb

ftest

fidis

plloff

led[2]/time-overflow

Vdd

Vss

time-signalb

led[0]/microtick

led[1]/time-tick

mtest

ram-address[0]

ram-address[1]

ram-address[2]

ram-ceb

Vss

Vdd

ram-data[15]

ram-data[14]

ram-data[13]

ram-data[12]

n.c.

n.c.

to Vdd

to Vss

ram-readyb

ram-web

ram-oeb

ram-data[11]

ram-data[10]

1

20

21

40

41

60

61

80

Vss

xin1

xout1

Vdd

ram-data[9]

ram-data[8]

Vss

Vdd

Figure 2 TQFP 80 pin package and pin assignment