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MC68HC908AT32 Datasheet, PDF (298/378 Pages) Freescale Semiconductor, Inc – Microcontrollers | |||
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Timer Interface (TIM-6)
25.8 I/O Registers
These I/O registers control and monitor TIMA operation:
⢠TIMA status and control register (TASC)
⢠TIMA control registers (TACNTHâTACNTL)
⢠TIMA counter modulo registers (TAMODHâTAMODL)
⢠TIMA channel status and control registers (TASC0, TASC1, TASC2, TASC3, TASC4, and TSAC5)
⢠TIMA channel registers (TACH0HâTACH0L, TACH1HâTACH1L, TACH2HâTACH2L,
TACH3HâTACH3L, TACH4HâTACH4L, and TACH5HâTACH5L)
25.8.1 TIMA Status and Control Register
The TIMA status and control register:
⢠Enables TIMA overflow interrupts
⢠Flags TIMA overflows
⢠Stops the TIMA counter
⢠Resets the TIMA counter
⢠Prescales the TIMA counter clock
Address: $0020
Bit 7
6
5
4
3
Read: TOF
0
0
TOIE TSTOP
Write: 0
TRST
R
2
1
Bit 0
PS2
PS1
PS0
Reset: 0
0
1
0
0
0
0
0
R
= Reserved
Figure 25-4. TIMA Status and Control Register (TASC)
TOF â TIMA Overflow Flag
This read/write flag is set when the TIMA counter resets to $0000 after reaching the modulo value
programmed in the TIMA counter modulo registers. Clear TOF by reading the TIMA status and control
register when TOF is set and then writing a logic 0 to TOF. If another TIMA overflow occurs before the
clearing sequence is complete, then writing logic 0 to TOF has no effect. Therefore, a TOF interrupt
request cannot be lost due to inadvertent clearing of TOF. Reset clears the TOF bit. Writing a logic 1
to TOF has no effect.
1 = TIMA counter has reached modulo value.
0 = TIMA counter has not reached modulo value.
TOIE â TIMA Overflow Interrupt Enable Bit
This read/write bit enables TIMA overflow interrupts when the TOF bit becomes set. Reset clears the
TOIE bit.
1 = TIMA overflow interrupts enabled
0 = TIMA overflow interrupts disabled
MC68HC908AT32 Data Sheet, Rev. 3.1
298
Freescale Semiconductor
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