9S08AW to 9S08AC anyone made the switch?

[TurboBob]

I have several projects using the AW,  but it looks like its going to be superceded by the AC.  The AC seems to be a little cheaper and its a Flexis part,  so it might make sense to switch at some point.

But,  I would want the firmware to be backwards compatible,  as the ones in the field may need updating sometime in the future and I would not want to maintain 2 sets of software,  let alone have the user try to determine which processor is installed.

I looked thru the datasheets and assorted docs,  but only got partial info.  It seems that the AC has a few more peripherals.

So,  to the question:   Has anyone made the switch?  What sort of hidden gotchas are in there?  Is there a way for the firmware to determine what hardware its running on in case there are differences that need to be accomodated?

The first application I was considering uses the AN2295 bootloader,  no timers/TPM channels ,  internal timebase,  internal flash to save data,  both UARTS,  and some analog inputs.  internal oscillator only.

Any hints?

Bob

[bigmac]

Hello Bob,

I have not used the 9S08AC series myself, however I can observe the following differences, some of which may be inconsequential to your existing code.  Firstly, I assume that you would use the 'AC60, rather than the 'AC128 with its banked memory complications.

The 'AC60 has a new CRC module, that presumably you can ignore.  It also has an extra TPM3 module.

Some of the modules have newer versions within the 'AC60, compared to the 'AW60.  These differences would need to be checked to see whether they had any bearing on your existing code.

Module:     'AW60  'AC60

IIC          V1     V2

SCI1, SCI2   V2     V4

TPM1, TPM2   V2     V3

For the TPM modules, the newer reference manual does describe the "migration" process required.  If you need to modify the existing code, it may still be possible that the modified code would still be satisfactory for the AW device.

I also notice that the 'AC60 has a choice of two COP timer sources, a 1kHz clock, in addition to the bus clock source.  The selection is controlled by a new SOPT2 register, with default to the bus clock - which is the only source for the 'AW60.

Note that it is feasible for your code to determine which of the two device types is installed, by means of the hard-coded SDID register.

Regards,

Mac