
5.0-Volt Control Timing
MC68HC908GR60A MC68HC908GR48A MC68HC908GR32A Data Sheet, Rev. 5
Freescale Semiconductor
283
20.7 5.0-Volt Control Timing
20.8 3.3-Volt Control Timing
Figure 20-1. RST and IRQ Timing
Characteristic(1)
1. VSS = 0 Vdc; timing shown with respect to 20% VDD and 70% VDD unless otherwise noted.
Symbol
Min
Max
Unit
Frequency of operation
Crystal option
External clock option(2)
2. No more than 10% duty cycle deviation from 50%.
fOSC
1
dc
8
32
MHz
Internal operating frequency
fOP (fBus)
—8
MHz
Internal clock period (1/fOP)tCYC
125
—
ns
RESET input pulse width low
tRL
100
—
ns
IRQ interrupt pulse width low (edge-triggered)
tILIH
100
—
ns
IRQ interrupt pulse period(3)
3. The minimum period is the number of cycles it takes to execute the interrupt service routine plus 1 tCYC.
tILIL
Note 3
—
tCYC
Characteristic(1)
1. VSS = 0 Vdc; timing shown with respect to 20% VDD and 70% VDD unless otherwise noted.
Symbol
Min
Max
Unit
Frequency of operation
Crystal option
External clock option(2)
2. No more than 10% duty cycle deviation from 50%.
fOSC
1
dc
8
16
MHz
Internal operating frequency
fOP (fBus)
—4
MHz
Internal clock period (1/fOP)tCYC
250
—
ns
RESET input pulse width low
tRL
200
—
ns
IRQ interrupt pulse width low (edge-triggered)
tILIH
200
—
ns
IRQ interrupt pulse period(3)
3. The minimum period is the number of cycles it takes to execute the interrupt service routine plus 1 tCYC.
tILIL
Note 3
—
tCYC
RST
IRQ
tRL
tILIH
tILIL