Selecting channel IO pin for external source of TPM - MC9S08DZ60

[TOK]

The documentation on the MC9S08DZ with the TPMV3 is unclear on how to select one of the available channel IO pins instead of the dedicated extern clock pin for the TPM (which is not available in the 32 pin package). It just tells not to use the pin as channel input, of course, but not how to select the pin. All it says is:

"The external clock source may be connected to any TPM channel pin."

and

"The external clock signal shares the same pin as a channel I/O pin, so the channel pin will not be usable
for channel I/O function when selected as the external clock source. [..] If this pin is used as an external clock source (CLKSB:CLKSA = 1:1), the channel can still be used in output compare mode as a software timer (ELSnB:ELSnA = 0:0)."

The block diagram also doesn't show any MUX or selection mechanism. Neither does the parallel port pin section of port D, where the channel pins are located as alternate function.

Any hints?

Thank you!

Thomas

Added p/n to subject.

Message Edited by NLFSJ on 2008-10-22 06:48 AM

[TOK]

Thank you for your quick response!!

So it is not possible to select the channel IO pin? Just if the TPMxCLK has been hardwired to a channel IO pin and the above text should have been:

"The external clock source might be connected to a TPM channel pin."

and

"If the external clock signal shares the same pin as a channel I/O pin, that channel pin will not be usable
for channel I/O function when selected as the external clock source. "


THIS REALLY IS MISSLEADING and I wasted several hours on that matter.

Thank you anyhow!

Thomas.

[Ake]

Hi,

I guess I am going blind, but I can't find the two sentences

"The external clock source might be connected to a TPM channel pin." and

"If the external clock signal shares the same pin as a channel I/O pin, that channel pin will not be usable
for channel I/O function when selected as the external clock source"

 in the latest rev 4, MC9S08DZ60 book, but could not find it.

I got to be able to find it, or I have a hard time complaining to our literature people.

Can you help me?

Regards,

Ake

[Ake]

Hi,

If you look at Figure 2-4 in the MC9S08DZ60 book, you willl find that the external TPM clock inputs are available on PTF2/TPM1CLK and PTF3/TPM2CLK, but those signals  have not been bonded out on the 32 pin package.

They are availble on the 64 pin and the 48 pin package.

I will tell our literature people about this miss in Timer/PWM module.

Thanks!

Regards,

Ake