Intel 80C188XL, 80C186XL user manual Clkout

Models: 80C186XL 80C188XL

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BUS INTERFACE UNIT

 

 

 

 

 

 

 

T1

TI

TI

 

CLKOUT

 

 

 

 

 

 

 

 

 

 

 

ALE

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

S2:0

 

 

011

 

 

 

 

 

 

AD15:0

 

 

 

 

 

 

 

 

 

 

 

 

 

Note 1

 

 

 

[AD7:0]

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

[A15:8]

 

 

 

 

 

 

 

 

 

 

 

 

Note 1

 

 

 

A19:16

 

 

 

 

 

 

 

 

 

 

 

 

Note 2

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

BHE

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

[RFSH = 1]

NOTES:

1.The AD15:0 [AD7:0] bus can be floating, driving a previous write data value, or driving the next instruction prefetch address value. For an 8-bit device, A15:8 drives either the previous bus address value or the next instruction prefetch address value.

2.The A19:16 bus drives either zero (all low) or 8H (all low except A19/S6, which can be high if the previous bus cycle was a DMA or refresh operation).

A1513-0A

Figure 3-25. HALT Bus Cycle

Table 3-6. HALT Bus Cycle Pin States

 

 

 

 

 

 

 

Pin(s)

Pin State

 

 

 

 

AD15:0 (AD7:0 for 8-bit)

Float

 

 

 

 

A15:8 (8-bit)

Drive Address

 

 

 

 

A19:16

Drive 8H or Zero

 

 

 

 

 

 

 

 

 

 

(16-bit)

Drive Last Value

 

BHE

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Drive One

 

RD,

WR,

DEN,

DT/R,

 

RFSH (8-bit), S2:0

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

3-29

Page 110
Image 110
Intel 80C188XL, 80C186XL user manual Clkout