MC908AS60ACFU Datasheet, PDF (239/414 Pages) Freescale Semiconductor, Inc – M68HC08 Microcontrollers

I/O Registers
Register Name and Address
Bit 7
6
Read: CH0F
Write: 0
CH0IE
Reset: 0
0
TBSC0 — $0045
5
4
MS0B MS0A
0
0
3
ELS0B
0
2
ELS0A
0
1
TOV0
0
Bit 0
CH0MAX
0
Register Name and Address
TBSC1 — $0048
Bit 7
6
5
4
3
2
1
Bit 0
Read: CH1F
0
CH1IE
MS1A ELS1B ELS1A TOV1 CH1MAX
Write: 0
R
Reset: 0
0
0
0
0
0
0
0
R = Reserved
Figure 20-7. TIMB Channel Status and Control Registers (TBSC0–TBSC1)
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
TIMB counter registers matches the value in the TIMB channel x registers.
When CHxIE = 1, clear CHxF by reading TIMB 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 TIMB CPU interrupts 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 TIMB
channel 0.
Setting MS0B disables the channel 1 status and control register and reverts TBCH1 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
compare/PWM operation (see Table 20-2).
1 = Unbuffered output compare/PWM operation
0 = Input capture operation
MC68HC908AZ60A • MC68HC908AS60A • MC68HC908AS60E Data Sheet, Rev. 6
Freescale Semiconductor
239