Maxim Integrated DS80C390 - Manual (Page 55)

DS80C390
55 of 58 110199
EXPLANATION OF AC SYMBOLS
This microcontroller uses timing parameters and symbols similar to the original 8051 family. The
following list of timing symbols is provided as an aid to understanding the timing diagrams.
t Time P
PSEN
A Address Q Output data
C Clock R
RD signal
CE Chip Enable V Valid
D Input data W
WR signal
H Logic level high X No longer a valid logic level
L Logic level low Z Tristate
I Instruction
POWER CYCLE TIMING CHARACTERISTICS
PARAMETER SYMBOL TYP MAX UNITS NOTE
Crystal start-up time t
CSU
1.8 ms 1
Power-on reset delay t
POR
65536 t
CLCL
2
NOTES FOR POWER CYCLE TIMING CHARACTERISTICS
1. Start-up time for crystals varies with load capacitance and manufacturer. Time shown is for an
11.0592 MHz crystal manufactured by Fox Electronics.
2. Reset delay is a synchronous counter of crystal oscillations during crystal start-up. Counting begins
when the level on the XTAL1 input meets the V
IH2
criteria. At 40 MHz, this time is approximately
1.64 ms.
POWER CYCLE TIMING