Intel 80C196NU, 8XC196NP, Microcontroller Symbol Definition 8XC196Nx Meets These Specifications

Models: Microcontroller 80C196NU 8XC196NP

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INTERFACING WITH EXTERNAL MEMORY

 

Table 13-16. AC Timing Definitions (Continued)

 

 

Symbol

Definition

 

 

 

The 8XC196Nx Meets These Specifications

 

 

f

Operating frequency

 

Frequency of the signal input on the XTAL1 pin times the clock multiplier (x). For the

 

8XC196NP, x is always 1; for the 80C196NU, x is 1, 2, or 4, depending on the clock mode. The

 

internal bus speed of the device is ½ f.

 

 

t

Operating period (1/f)

 

All AC Timings are referenced to t.

 

 

TAVLL

Address Setup to ALE Low

 

Length of time ADDRESS is valid before ALE falls. Use this specification when designing the

 

external latch.

 

 

TAVRL

Address Setup to RD# Low

 

Length of time ADDRESS is valid before RD# falls.

 

 

TAVWL

Address Setup to WR# Low

 

Length of time ADDRESS is valid before WR# falls.

 

 

TCHCL

CLKOUT High Period

 

Needed in systems that use CLKOUT as clock for external devices.

 

 

TCHWL

CLKOUT High to WR# Low

 

Time between CLKOUT going high and WR# going active.

 

 

TCLCL

CLKOUT Cycle Time

 

Normally 2t.

 

 

TCLLH

CLKOUT Falling to ALE Rising

 

Use to derive other timings.

 

 

TLHLH

ALE Cycle Time

 

Minimum time between ALE pulses.

 

 

TLHLL

ALE High Period

 

Use this specification when designing the external latch.

 

 

TLLAX

Address Hold after ALE Low

 

Length of time ADDRESS is valid after ALE falls. Use this specification when designing the

 

external latch.

 

 

TLLCH

ALE Falling to CLKOUT Rising

 

Use to derive other timings.

 

 

TLLRL

ALE Low to RD# Low

 

Length of time after ALE falls before RD# is asserted. Could be needed to ensure proper

 

memory decoding takes place before a device is enabled.

 

 

TLLWL

ALE Low to WR# Low

 

Length of time after ALE falls before WR# is asserted. Could be needed to ensure proper

 

memory decoding takes place before a device is enabled.

 

 

13-43

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Intel 80C196NU, 8XC196NP, Microcontroller manual Symbol Definition 8XC196Nx Meets These Specifications