Compaq 21264, EV67 specifications Testability and Diagnostics, Test Pins, Dedicated Test Port Pins

11

Testability and Diagnostics

This chapter describes the 21264/EV67 user-oriented testability and diagnostic fea- tures. These features include automatic power-up self-test, Icache initialization from external serial ROMs, and the serial diagnostic terminal port.

The boundary-scan register, which is another testability and diagnostic feature, is listed in Appendix B. The boundary-scan register is compatible with IEEE Standard 1149.1.

This chapter is organized as follows:

•Test pins

•SROM/serial diagnostic terminal port

•IEEE 1149.1 port

•TestStat_H pin

•Power-up self-test and initialization

•Notes on IEEE 1149.1 operation and compliance

The 21264/EV67 has several manufacturing test features that are used only by the fac- tory, and they are beyond the scope of this chapter.

11.1 Test Pins

The 21264/EV67 test access ports include the IEEE 1149.1 test access port, a dual-pur- pose SROM/Serial diagnostic terminal port, and a test status output pin. Table 11–1lists the test access port pins.

Table 11–1 Dedicated Test Port Pins

Pin Name	Type	Function
Tms_H	Input	IEEE 1149.1 test mode select
Tdi_H	Input	IEEE 1149.1 test data in
Trst_L	Input	IEEE 1149.1 test logic reset
Tck_H	Input	IEEE 1149.1 test clock
Tdo_H	Output	IEEE 1149.1 test data output
SromData_H	Input	SROM data/Diagnostic terminal data input

Alpha 21264/EV67 Hardware Reference Manual Testability and Diagnostics 11–1