Freescale Semiconductor MC68HC08KH12 User Manual

Page 179

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MC68HC(7)08KH12

Rev. 1.1

Advance Information

Freescale Semiconductor

179

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 compare/PWM operation.
See

Table 11-3

.

1 = Unbuffered output compare/PWM operation
0 = Input capture operation

When ELSxB:A = 00, this read/write bit selects the initial output level
of the TCHx pin.

(See Table 11-3.)

. Reset clears the MSxA bit.

1 = Initial output level low
0 = Initial output level high

NOTE:

Before changing a channel function by writing to the MSxB or MSxA bit,
set the TSTOP and TRST bits in the TIM status and control register
(TSC).

ELSxB and ELSxA — Edge/Level Select Bits

When channel x is an input capture channel, these read/write bits
control the active edge-sensing logic on channel x.

When channel x is an output compare channel, ELSxB and ELSxA
control the channel x output behavior when an output compare
occurs.

When ELSxB and ELSxA are both clear, channel x is not connected
to port E, and pin PTEx/TCHx is available as a general-purpose I/O
pin.

Table 11-3

shows how ELSxB and ELSxA work. Reset clears the

ELSxB and ELSxA bits.

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