INTERFACING WITH EXTERNAL MEMORY

 

Table 15-9. Microcontroller Meets These Specifications (Continued)

 

 

Symbol

Definition

 

 

TWHAX

Address (high byte) Hold after WR# High

 

Minimum time the high byte of the address (when using an 8-bit data bus) is valid after the

 

microcontroller deasserts WR#.

 

 

TWHBX

BHE#, INST Hold after WR# High

 

Minimum time these signals are valid after the microcontroller deasserts WR#.

 

 

TWHLH

WR# High to ALE High

 

Time between the microcontroller deasserting WR# and next ALE pulse. Maximum time the

 

memory system has to get data off the bus before the next address cycle.

 

 

TWHQX

Output Data Hold after WR# High

 

Length of time output data is valid on the bus after the microcontroller deasserts WR#.

 

 

TWLWH

WR# Low to WR# High

 

WR# pulse width.

 

 

XTAL1 High to CLKOUT High or Low

TXHCH

TXTAL1

1/FXTAL1

 

The period of the frequency on the XTAL1 input (FXTAL1). All AC timings are referenced to

 

TXTAL1.

The CLKOUT pin is available only on the 8XC196MC, MD microcontrollers.

15-35

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Intel 8XC196MC, 8XC196MD, 8XC196MH manual 15-35