TTP-C2NF Communication Controller – Data Sheet

AS8202NF

Rev. 1.7, Copyright 2000-2007, austriamicrosystems AG and TTChip Entwicklungsgesellschaft mbH. All rights reserved.

17

8.7.

LED Signals

The LED port consists of three pins. Via the MEDL each of these pins can be independently

configured for any of the three modes of operation. At Power-Up and after Reset the LED port

is inactive and only weak pull-down resistors are connected. After the controller is switched on

by the host and when it is processing its initialization, the LED port is initialized to the selected

mode of operation.

Pin Name

Protocol Mode

Timing Mode

Bus Guardian Mode

LED2

LED1

LED0

Note 1: RPV is Remote Pin Voting. RPV is a network-wide agreed signal used typically for agreed power-up or power-down of the application's external

drivers.

Note 2: Time Overflow is active for one clock cycle at the event of an overflow of the internal 16-bit time counter. Time Tick is active for one clock cycle

when the internal time is counted up. Time Overflow and Time Tick can be used to externally clone the internal time control unit (TCU). With

this information the application can precisely sample and trigger events, for example.

Note 3: Microtick is the internal main clock signal.

Note 4: Action Time signals the start of a bus access cycle.

Note 5: BDE0 and BDE1 show the Bus Guardian's activity, '1' signals an activated transmitter gate on the respective channel.

Note 6: Protocol activity is typically connected to an optical LED. The flashing frequency and rhythm give a simple view to the internal TTP protocol

state.

Note 7: LED2's RPV mode and LED0's Protocol activity mode can be swapped with a MEDL parameter.

Note 8: The controller sets this output when cluster synchronization is achieved (after integration from the LISTEN state, after acknowledge in the

COLDSTART state).

Each LED pin can be configured to be either a push/pull driver (drives both LOW and HIGH) or

to be only an open-drain output (drives only LOW).