Rainbow-electronics W78C52D Bedienungsanleitung PDF herunterladen (Seite 11)

Preliminary W78C52D

Publication Release Date: December 1998

- 11 - Revision A1

AC CHARACTERISTICS

The AC specifications are a function of the particular process used to manufacture the part, the

ratings of the I/O buffers, the capacitive load, and the internal routing capacitance. Most of the

specifications can be expressed in terms of multiple input clock periods (TCP), and actual parts will

usually experience less than a ±20 nS variation. The numbers below represent the performance

expected from a 0.5 micron CMOS process when using 2 and 4 mA output buffers.

Clock Input Waveform

XTAL1

OP,

PARAMETER SYMBOL MIN. TYP. MAX. UNIT NOTES

Operating Speed FOP 0 - 24 MHz 1

Clock Period TCP 25 - - nS 2

Clock High TCH 10 - - nS 3

Clock Low TCL 10 - - nS 3

Notes:

1. The clock may be stopped indefinitely in either state.

2. The T

CP specification is used as a reference in other specifications.

3. There are no duty cycle requirements on the XTAL1 input.

Program Fetch Cycle

PARAMETER SYMBOL MIN. TYP. MAX. UNIT NOTES

Address Valid to ALE Low TAAS

1 TCP-∆

--nS4

Address Hold from ALE Low TAAH

1 TCP-∆

- - nS 1, 4

ALE Low to PSEN Low

APL

1 TCP-∆

--nS4

PSEN Low to Data Valid

PDA --2 TCP nS 2

Data Hold after PSEN High

PDH 0 -1 TCP nS 3

Data Float after PSEN High

PDZ 0 -1 TCP nS

ALE Pulse Width TALW

2 TCP-∆

2 T

CP - nS 4

PSEN Pulse Width

PSW

3 TCP-∆

3 T

CP -nS4

Notes:

1. P0.0−P0.7, P2.0−P2.7 remain stable throughout entire memory cycle.

2. Memory access time is 3 T

CP.

3. Data have been latched internally prior to

PSEN going high.

4. "∆" (due to buffer driving delay and wire loading) is 20 nS.

1 2 ... 6 7 8 9 10 11 12 13 14 15 16 17 18

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