Datasheet
Timer Interface Module (TIM)
MC68HC908AP Family Data Sheet, Rev. 4
146 Freescale Semiconductor
9.9.4 TIM Channel Status and Control Registers
Each of the TIM channel status and control registers:
• Flags input captures and output compares
• Enables input capture and output compare interrupts
• Selects input capture, output compare, or PWM operation
• Selects high, low, or toggling output on output compare
• Selects rising edge, falling edge, or any edge as the active input capture trigger
• Selects output toggling on TIM overflow
• Selects 0% and 100% PWM duty cycle
• Selects buffered or unbuffered output compare/PWM operation
CHxF — Channel x Flag Bit
When channel x is an input capture channel, this read/write bit is set when an active edge occurs on
the channel x pin. When channel x is an output compare channel, CHxF is set when the value in the
TIM counter registers matches the value in the TIM channel x registers.
When TIM CPU interrupt requests are enabled (CHxIE = 1), clear CHxF by reading TIM channel x
status and control register with CHxF set and then writing a logic 0 to CHxF. If another interrupt request
occurs before the clearing sequence is complete, then writing logic 0 to CHxF has no effect. Therefore,
an interrupt request cannot be lost due to inadvertent clearing of CHxF.
Reset clears the CHxF bit. Writing a logic 1 to CHxF has no effect.
1 = Input capture or output compare on channel x
0 = No input capture or output compare on channel x
CHxIE — Channel x Interrupt Enable Bit
This read/write bit enables TIM CPU interrupt service requests on channel x.
Reset clears the CHxIE bit.
1 = Channel x CPU interrupt requests enabled
0 = Channel x CPU interrupt requests disabled
MSxB — Mode Select Bit B
This read/write bit selects buffered output compare/PWM operation. MSxB exists only in the TIM1
channel 0 and TIM2 channel 0 status and control registers.
Address: T1SC0, $0025 and T2SC0, $0030
Bit 7654321Bit 0
Read: CH0F
CH0IE MS0B MS0A ELS0B ELS0A TOV0 CH0MAX
Write: 0
Reset:00000000
Figure 9-9. TIM Channel 0 Status and Control Register (TSC0)
Address: T1SC1, $0028 and T2SC1, $0033
Bit 7654321Bit 0
Read: CH1F
CH1IE
0
MS1A ELS1B ELS1A TOV1 CH1MAX
Write: 0
Reset:00000000
Figure 9-10. TIM Channel 1 Status and Control Register (TSC1)