Signal Descriptions
5-131
18524C/0—Nov1996
AMD-K5 Processor Technical Reference Manual
5.2.54
TRST (Test Reset)
Input
Summary
The assertion of TRST initializes the Test Access Port (TAP) by
resetting its state machine.
Sampled
TRST is an asynchronous input. Unlike other asynchronous
inputs, no synchronous setup and hold time are specified for
TRST. TRST has an internal pullup resistor.
TRST is always sampled, except while RESET or INIT is
asserted.
Details
When TRST is asserted, the TAP controller enters its test-
reset-logic state, regardless of the controller state. This action
is the same as that achieved by holding TMS asserted for five
or more clocks. The assertion of TRST is unnecessary at
RESET because the processor performs the TAP reset auto-
matically at that point.
See the IEEE Standard Test Access Port and Boundary-Scan
Architecture (IEEE 1149.1) specification for a description of
how the TAP signals and instructions are used for testing.
Summary of Contents for AMD-K5
Page 1: ...AMD K5 Processor Technical Reference Manual TM...
Page 10: ...x AMD K5 Processor Technical Reference Manual 18524C 0 Nov1996...
Page 24: ...1 4 Overview AMD K5 Processor Technical Reference Manual 18524C 0 Nov1996...
Page 54: ...2 30 Internal Architecture AMD K5 Processor Technical Reference Manual 18524C 0 Nov1996...
Page 116: ...4 26 Performance AMD K5 Processor Technical Reference Manual 18524C 0 Nov1996...
Page 356: ...6 44 System Design AMD K5 Processor Technical Reference Manual 18524C 0 Nov1996...
Page 380: ...7 24 Test and Debug AMD K5 Processor Technical Reference Manual 18524C 0 Nov1996...
Page 396: ...A 16 AMD K5 Processor Technical Reference Manual 18524C 0 Nov1996...
Page 406: ...I 10 Index AMD K5 Processor Technical Reference Manual 18524C 0 Nov1996...