need some advice

[mikeradio]

Hello

I have been given the task of updating a two-way radio that my company produces.  Currently we use the

MC68HC908AP32.  Should I keep using it or update to a new one that is HCS08?  I need to get about 5 more years of production and I am worried the MC68HC908AP32 wont be around.  And what would be a good replacment?

Thank you

Mike

[bigmac]

Hello Mike, and welcome to the forum.

Your concerns are probably warranted since the device you are using is currently classified "not recommended for new design".

The choice of a new 8-bit MCU type from the more recent 9S08 family will probably depend on which of the more "exotic" features of the current MCU that you are actually using.  Within this category I would place -

1. The IR encoder/decoder operation associated with one of the SCI modules.
2. The IRQ2 input pin.
3. The 25mA open drain output pins.

It is also unclear to me how the SMBus requirements differ from standard IIC module operation, should you make use of this feature.  You will also need to consider whether a FLL can replace a PLL for your application.  The FLL will have considerably more short term phase jitter.

The TBM functionality for the current device might be substitued by an RTC module.

Another important consideration would be whether the scope of the product re-design can accommodate 3.3 volt operation in lieu of 5 volt operation.  If not, this would limit the MCU choice.

As a starting point, you might consider the 9S08ACxx for 5 volt operation, or the 9S08QExx for 3.3 volt operation.

Regards,

Mac