Power-Up Self-Test And Initialization; Built-In Self-Test; Alpha 21264/Ev67 Hardware Reference Manual; Srom Initialization - Compaq 21264 Hardware Reference Manual

Figure 11–2 TestStat_H Pin Timing During Power-Up Built-In Self-Test (BiST)
ClkFwdReset_L
Tbox_Reset_A_L
TBox Reset Engine
Idle
TestStatus_H
Figure 11–3 TestStat_H Pin Timing During Built-In Self-Initialization (BiSI)
Tbox_Rst_A_L1
TBox Reset Engine1
Idle
TestStatus_H1
ClkFwdRst_L1

11.5 Power-Up Self-Test and Initialization

Upon powering up, the 21264/EV67 automatically performs the self-test of all major
embedded RAM arrays and then loads the Cbox configuration registers and the instruc-
tion cache from the system SROM. The chip's internal logic is held in reset during
these operations. See Chapter 9 for sequencing of power-up operations.

11.5.1 Built-in Self-Test

The power-up self-test is performed on the instruction cache and tag arrays, the data
cache and tag arrays, the triplicate tag arrays, and the various RAM arrays located in the
branch history table logic. The power-up self-test lasts for approximately 700,000 CPU
cycles. The result of self-test is made available as Pass/Fail status on the TestStat_H
pin (see Section 11.4).
The result of self-test is also available in an IPR bit. Software can read this status
through IPR I_CTL(23) (0 = pass, 1 = fail). See Section 5.2.15.
The power-up BiST leaves all bits in all arrays initialized to zeroes. The instruction
cache and the tag are reinitialized as part of the SROM initialization step. This is
detailed in Section 11.5.2.

11.5.2 SROM Initialization

Power-up initialization on the 21264/EV67 is different from previous generation Alpha
systems in two aspects. First, in the 21264/EV67 systems, the presence of serial
ROMs is mandatory as initialization of several Cbox configuration registers depends on
them. Second, it is possible to skip or partially fill Icache from serial ROMs. Figure 11–
4 shows the map of the data in serial ROMs.

Alpha 21264/EV67 Hardware Reference Manual

Power-Up Self-Test and Initialization
DoBist DoResult
DoMfgSelfinit
DoSROM Idle
BiSTResult BiSTResult OR T
LKG-10950A-98WF
Idle
TimeOut
LKG-10951A-98WF
Testability and Diagnostics
11–5