BUS INTERFACE UNIT

The address/status phase starts just before T1 and continues through T1. The data phase starts at T2 and continues through T4. Figure 3-9 illustrates the T-state relationship of the two phases.

T4

 

 

Bus Ready

 

 

Request Pending

 

 

HOLD Deasserted

 

Halt Bus Cycle

 

T1

T2

T3

 

 

Bus Not

 

 

Ready

Request Pending

 

Bus Ready

HOLD Deasserted

 

No Request Pending

 

TI

HOLD Deasserted

 

 

RES#

 

 

Asserted

 

 

HOLD Asserted

A1533-02

Figure 3-8. BIU State Diagram

3-9

Page 90
Image 90
Intel 80C188XL, 80C186XL user manual Bus Ready, Request Pending, Hold Deasserted, Res#, Asserted Hold Asserted