S12XA256: Reducing power consumption?

[pittbull]

Hello,
I'm running an S12XA256 that only uses one SCI and some GPIO's. Are there any modules enabled by default which I can disable to reduce current consumption (e.g. the internal EEPROM)?

Thanks in advance,
pittbull

BTW: Something like Stop- and Wait-Modes are not suitable because the CPU must continue to run...

[rhinoceroshead]

The only way I can think of to reduce current consumption out of reset without using stop or wait modes would be to reduce the clock frequency (using the PLL) to the minimum required for your situation.

As far as I know, all modules that can be disabled are already disabled out of reset.

[pittbull]

Hi Rhino,

I decreased the bus frequency from 40Mhz down to 18Mhz (fewer speed does not work in my situation). This saves 50mA.

I also tried to enable reduced drive strength on all I/O's but that doesn't help...

Thanks a lot,
pittbull

Message Edited by pittbull on 2006-06-27 05:27 AM

[rhinoceroshead]

What are you driving with the GPI/O pins?  Are you using the XGATE?  If you aren't using it then I wonder if an S12 with less RAM would use less current.  I don't have any laying around on boards so I can't compare.  I do have an S12XDP512 if you want to know how much current it uses out of reset.

[pittbull]

Hi,

It is a self-made board that drives a WLAN card. Supply voltage is a single 3.3V source for all components. The overall current consumption is 280mA when running with 18Mhz and 330mA @ 40Mhz. I'm not using the XGATE.

I think that dramatic savings of 50mA is because the WLAN module is driven rarer at 18Mhz...