Timer Interface Module (TIM)
MC68HC908QY/QT Family Data Sheet, Rev. 5
130
Freescale Semiconductor
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.
Clear CHxF by reading the TIM channel x status and control register with CHxF set and then writing
a 0 to CHxF. If another interrupt request occurs before the clearing sequence is complete, then writing
a 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 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 TIM
channel 0 status and control register.
Setting MS0B disables the channel 1 status and control register and reverts TCH1 to general-purpose
I/O.
Reset clears the MSxB bit.
1 = Buffered output compare/PWM operation enabled
0 = Buffered output compare/PWM operation disabled
MSxA — Mode Select Bit A
When ELSxB:A
≠ 00, this read/write bit selects either input capture operation or unbuffered output
1 = Unbuffered output compare/PWM operation
0 = Input capture operation
Address: $0025
TSC0
Bit 7
654321
Bit 0
Read:
CH0F
CH0IE
MS0B
MS0A
ELS0B
ELS0A
TOV0
CH0MAX
Write:
0
Reset:
00000000
Address: $0028
TSC1
Bit 7
654321
Bit 0
Read:
CH1F
CH1IE
0
MS1A
ELS1B
ELS1A
TOV1
CH1MAX
Write:
0
Reset:
00000000
= Unimplemented
Figure 14-7. TIM Channel Status and Control
Registers (TSC0:TSC1)