REGISTER SUMMARY
M68HC16 Z SERIES
D-14
USER’S MANUAL
PIV[7:0] — Periodic Interrupt Vector
This field specifies the periodic interrupt vector number supplied by the SIM when the
CPU16 acknowledges an interrupt request.
D.2.14 Periodic Interrupt Timer Register
Contains the count value for the periodic timer. This register can be read or written at
any time.
PTP — Periodic Timer Prescaler
0 = Periodic timer clock not prescaled.
1 = Periodic timer clock prescaled by a value of 512.
PITM[7:0] — Periodic Interrupt Timing Modulus
This field determines the periodic interrupt rate. Use the following equations to calcu-
late timer period.
The following equation calculates the PIT period when a slow reference frequency is
used:
The following equation calculates the PIT period when a fast reference frequency is
used:
The following equation calculates the PIT period for an externally input clock frequen-
cy on both slow and fast reference frequency devices.
PITR — Periodic Interrupt Timer Register
$YFFA24
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
0
0
0
0
0
0
0
PTP
PITM[7:0]
RESET:
0
0
0
0
0
0
0
MODCLK
0
0
0
0
0
0
0
0
PIT Period
PITM[7:0]
(
)
1 if PTP = 0, 512 if PTP = 1
(
)
4
( )
f
ref
---------------------------------------------------------------------------------------------------------------------
=
PIT Period
128
(
)
PITM[7:0]
(
)
1 if PTP = 0, 512 if PTP = 1
(
)
4
( )
f
ref
------------------------------------------------------------------------------------------------------------------------------------
=
PIT Period
PITM[7:0]
(
)
1 if PTP = 0, 512 if PTP = 1
(
)
4
( )
f
sys
---------------------------------------------------------------------------------------------------------------------
=
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Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
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