mtbballer

This is a breakout of the super long "Axim PXBus set to 100Mhz by default??"

As a quick overview, the LMN settings are multiplier settings to the 3.6864 MHz Oscillator (the primary clock source for your processor). L is the Memory frequency multipler. M is the Run mode (normal) frequency multipler. N is the Turbo mode frequency multiplier. Here's how they work:

Your CPU/Memory/Bus speed are functions of each other. Your memory speed is determined by multiplying the L value times 3.6864 Mhz. Your Run mode speed is determined by multiplying the memory speed times the M value. The Turbo mode is the Run mode speed times the N value.

With that in mind determine your processor type (PXA250 or PXA255)

http://developer.intel.com/design/pc...uals/index.htm

For PXA255, refer to pages 66-67 of the PXA255 Developer's Manual.

For PXA250, refer to pages 72-73 of the PXA250 Developer's Manual.

Look at table 3-1 in for your processor. You'll see that there are various settings that you can make your LMN settings to. You'll also see the resultant speed of the processor, PX Bus, LCD/MEM, and SDRAM.

Without going too far into overclocking, a sample of it would be changing the LMN setting of 27,4,1 to 27,4,1.5. What does this do? Assuming you are using a PXA255, according to the table, your memory speed will be 196 (I know, it's not 27x3.6864). Your run mode will be the calculated speed - 27 (L) x 4 (M) x 3.6864 MHz - 398.1 MHz. The turbo speed will the be the run speed x the N value - 1.5, So 597.2 is the resultant turbo speed (compared to 398.1 when the N value was 1).

The problem with this is (and I suspect is why people are having problems) that running at 597.2 MHz it is out of the voltage range for the processor. The Axim gets overloaded and then craps out. Overclocking isn't necessarily a bad thing, but if you don't have an adequate power source and cooling, it's not very beneficial.

Sorry for the dissertation. I hope this clears the air on LMN settings and overclocking...