DIYEFI.org Forum

Fred wrote:You're right, they're obvious. No such code will be included in my, root-source, upstream, master source for FreeEMS. This decision, like all others, was made by community consultation, and the result was that the vast majority of users, at the time, agreed that it was a poor choice to implement this in the MCU. That remains true. Only people with sufficient understanding of all aspects involved should carry an opinion on this decision. I fit that bill.

Yes Fred. That was the obvious I was thinking about.

jharvey wrote:Thanks for the clarity in your reply. Rake was a term used by an ARM sales rep. Basically you setup a pointer to a section of memory. Then you set a DMA channel from that memory to the GPIO. The DMA controller can be set to increment the input memory location on each clock cycle, such that the next bit in memory is directly pushed to the GPIO pin.

Hey Jared, that idea is worth exploring. The method can be spread across a full I/O port, for both fuel and spark. And since I just posted those words, we now have independent credible confirmation for it on the internet.

Seriously though, maybe start a thread in Puma called '8cyl Sequential PWM and Spark on the Puma Processor'.

Fred wrote:Jared, I'm still lost on the raking. Can you please provide a link to a credible (the internet is full of non-credible sources...) source for this information (to save you time re-explaining something that is already explained on the net).

It does seem to be getting OT, but still applies I guess. I don't have any creditable references, for anything I do with software. If you would like to verify if this DMA raking is a myth or real potential PWM solution, perhaps you can call a FreeScale sales rep or application engineer. As you know I'm not an expert with this processors, or really any processor for that matter. My understanding of DMA is that many platforms can interconnect many things. The DMA raking was mentioned by an ARM guy, but I believe the technique is generic, and can be done with many different processors. That application in fact can not be done with all ARM's.

Can you give me a creditable reference for RS232? I've been looking for years, and can't seem to find one. Closest I've found is EIA232, which does not follow many applications. I know many applications that use 0V and 12V while EIA232 claims you must be + and - 12V. In the end, I often don't concern myself with credible references, I concern myself with a functional application first.

1997 TIA-232-F - you have to pay for it. Enjoy.

How about we make the next post relative to the LM1949 driving a FET instead of a transistor. My understanding is that it doesn't work well because of the high gain in the FET.