Intel 80C188XL, 80C186XL user manual 3.6SYSTEM DESIGN ALTERNATIVES, Clkout, Rfsh

Models: 80C186XL 80C188XL

1 405
Download 405 pages 42.62 Kb
Page 114
Image 114
NMI/INTx

BUS INTERFACE UNIT

CLKOUT

3.6SYSTEM DESIGN ALTERNATIVESManual background Note 1

NMI/INTx

ALE

S2:0

AD15:0

[AD7:0]

[A15:8]

A19:16

BHE

RFSH

 

Valid

Note 2

Addr

Note 2

Address

Note 2

Addr

Note 2

 

NOTES: 1. For NMI, delay = 4 1/2 clocks. For INTx, delay = 7 1/2 clocks (min). 2. Previous bus cycle value.

A1517-0A

Figure 3-29. Exiting HALT

3.6SYSTEM DESIGN ALTERNATIVES

Most system designs require no signals other than those already provided by the BIU. However, heavily loaded bus conditions, slow memory or peripheral device performance and off-board de- vice interfaces may not be supported directly without modifying the BIU interface. The following sections deal with topics to enhance or modify the operation of the BIU.

3-33

Page 114
Image 114
Intel 80C188XL, 80C186XL 3.6SYSTEM DESIGN ALTERNATIVES, Clkout, NMI/INTx ALE S2:0 AD15:0 AD7:0 A15:8 A19:16 BHE, Rfsh