Datasheet

Control Timing
MC68HC812A4 Data Sheet, Rev. 7
Freescale Semiconductor 227
18.11 Control Timing
Figure 18-1. Timer Inputs
Characteristic Symbol
8.0 MHz
Unit
Min Max
Frequency of operation
f
o
dc 8.0 MHz
E-clock period
t
cyc
125 — ns
Crystal frequency
f
XTAL
—16.0MHz
External oscillator frequency
2 f
o
dc 16.0 MHz
Processor control setup time
t
PCSU
= t
cyc
/2 + 30
t
PCSU
82 — ns
Reset input pulse width
To guarantee external reset vector
Minimum input time (can be pre-empted by internal reset)
PW
RSTL
32
2
—
—
t
cyc
Mode programming setup time
t
MPS
4—
t
cyc
Mode programming hold time
t
MPH
10 — ns
Interrupt pulse width, IRQ, edge-sensitive mode, KWU
PW
IRQ
= 2 t
cyc
+ 20
PW
IRQ
270 — ns
Wait recovery startup time t
WRS
—4t
cyc
Timer pulse width, input capture pulse accumulator input
PW
TIM
= 2 t
cyc
+ 20
PW
TIM
270 — ns
PT7
(2)
PT7
(1)
PT[7:0]
(2)
PT[7:0]
(1)
Notes:
1. Rising edge-sensitive input
2. Falling edge-sensitive input
PW
TIM
PW
PA