intJ80386

 

CYCLE 1

 

 

HOLD

 

CYCLE 2

 

PIPELINED

 

ACKNOWLEDGE

NON-PIPELINED

 

(WRITE)

 

 

 

 

(READ)

TIP

T21

T21

Th

Th

TI

T2

CLK2[

(82384 CLK) [

HOLD [

HLDA [

8EO#-8E3#, A2-A31, [

M/IO#, D/c#, W/R#

ADS# [

NA# [ ..Qja~-4~~~~~~~~~~~~

231630-31

NOTE:

HOLD is a synchronous input and can be asserted at any CLK2 edge, provided setup and hold (t23 and t24) require- ments are met. This waveform is useful for determining Hold Acknowledge latency.

Figure 5-27. Requesting Hold from Active Bus (NA # asserted)

5.6 SELF-TEST SIGNATURE

Upon completion of self-test, (if self-test was re- quested by holding BUSY # LOW at least eight CLK2 periods before and after the falling edge of RESET), the EAX register will contain a signature of OOOOOOOOh indicating the 80386 passed its self-test of microcode and major PLA contents with no prob- lems detected. The passing signature in EAX, OOOOOOOOh, applies to all 80386 revision levels. Any non-zero signature indicates the 80386 unit is faulty.

5.7COMPONENT AND REVISION IDENTIFIERS

To assist 80386 users, the 80386 after reset holds a component identifier and a revision identifier in its OX

register. The upper 8 bits of OX hold 03h as identifi- cation of the 80386 component. The lower 8 bits of OX hold an 8-bit unsigned binary number related to the component revision level. The revision identifier begins chronologically with a value zero and is sub- ject to change (typically it will be incremented) with component steppings intended to have certain im- provements or distinctions from previous steppings.

These features are intended to assist 80386 users to a practical extent. However, the revision identifier value is not guaranteed to change with every step- ping revision, or to follow a completely uniform nu- merical sequence, depending on the type or inten- tion of revision, or manufacturing materials required to be changed. Intel has sole discretion over these characteristics of the component.

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Intel 80386 manual SELF-TEST Signature, Component and Revision Identifiers