mcf51jf128 Freescale Semiconductor, Inc, mcf51jf128 Datasheet - Page 807

• Manufacturer Part Number: mcf51jf128
• Description: Mcf51jf128 Reference Manual
• Manufacturer: Freescale Semiconductor, Inc

37.3.4 Counter High (FTMx_CNTH)
The Counter registers contain the high and low bytes of the counter value. Reading either
byte latches the contents of both bytes into a buffer where they remain latched until the
other half is read. This allows coherent 16-bit reads in either big-endian or little-endian
order which makes this more friendly to various compiler implementations. The
coherency mechanism is automatically restarted by an MCU reset or any write to the
Status and Control register.
Freescale Semiconductor, Inc.
CPWMS
CLKS
TOIE
Field
4–3
2–0
PS
6
5
Timer Overflow Interrupt Enable
Enables FTM overflow interrupts.
0
1
Center-aligned PWM Select
Selects CPWM mode. This mode configures the FTM to operate in up-down counting mode.
CPWMS is write protected. It can be written only when MODE[WPDIS] = 1.
0
1
Clock Source Selection
Selects one of the three FTM counter clock sources.
CLKS is write protected. It can be written only when MODE[WPDIS] = 1.
00
01
10
11
Prescale Factor Selection
Selects one of 8 division factors for the clock source selected by CLKS. The new prescaler factor affects
the clock source on the next system clock cycle after the new value is updated into the register bits.
PS is write protected. It can be written only when MODE[WPDIS] = 1.
000
001
010
011
100
101
110
111
Disable TOF interrupts. Use software polling.
Enable TOF interrupts. An interrupt is generated when TOF equals one.
FTM counter operates in up counting mode.
FTM counter operates in up-down counting mode.
No clock selected (this in effect disables the FTM counter).
If MODE[FTMEN] = 0, the System clock divided by 2 is selected. If MODE[FTMEN] = 1, the System
clock is selected.
Fixed frequency clock
External clock
Divide by 1
Divide by 2
Divide by 4
Divide by 8
Divide by 16
Divide by 32
Divide by 64
Divide by 128
MCF51JF128 Reference Manual, Rev. 2, 03/2011
FTMx_SC field descriptions (continued)
Preliminary
Description
Chapter 37 FlexTimer (FTM)
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