CPU and hardware advice sought for EFI

The Punisher punisher454 at hotmail.com
Thu Feb 28 20:11:27 GMT 2002


It has been a long time since I looked at any tern SBC boards but the first 
number looked like a '586 ?(I didnt have time to check the links)
I know some hardcore assembly programmers are going to go off on me for 
writing this but I cant resist...

Are you sure you realy need a 32 or even 16 bit processor? I'll bet you 
could use an Atmel Atmega128 running at 16MHZ and acomplish evrything you 
need to do with a fraction of the development time and costs.
The ATMEGA will execute 1 instruction per clock which is quite good for most 
embedded processors. it would be dramaticly faster than a 68hc11 like is 
used in some GM's and even the aftermarket DFI computer(not the v7 its a 
68332).
you can get a ATMEGA128-16 (16MHZ) for about 15-16.00 if you shop around. 
The STK-500 development board/programmer is only 79.00 and the add on 
STK-501(needed for the 128's 64tqfp format and extra features)is a little 
over 80.00. You can get quite an array of c-compilers and even AVR-GCC (GNU 
C Compiler)for free. There are also some very good Pascal compilers and some 
decent basic compilers too. Compared to most other embedded compilers ATMEL 
AVR compilers are priced inexpensively.
There are a couple of RTOS for AVR's also but I'll bet that you could get 
away without one just by picking a fast compiler.
Obviously assembly is the most compact and fastest running(if you did it 
right). But I'd be willing to wager that something like FASTAVR basic on a 
ATMEGA128-16 (or even an ATMEGA16 when its available)will have enough code 
space and speed to handle youre engine managment system just fine.  And 
you'd be driving the thing while alot of guys would still be at the desk 
trying to get the TPU working just right (or something like that)on their 
68332 based board which will probably never get finished anyhow. Start basic 
and add features after you get one thing working right. Like get it to read 
the sensors and fire some injectors in batch fire mode first. Then add a cam 
sensor and use the built in counters and an interupt or two and get it doing 
sequential injection, THEN add in the ignition events and whatever else.
That aproach seems to be working for MEGASQUIRT unlike the "go for evrything 
all at once" aproach which is probably what kept EFI332 draging along at a 
snails pace for years and only a couple cars ever even started up.

okay now I guess the REAL (assembly) programers are going to have a heyday 
with this one. :)

Marvin Fugate (AMATURE 8-bit AVR and PIC embedded fan)



>From: David Gravereaux <davygrvy at pobox.com>
>Reply-To: diy_efi at diy-efi.org
>To: DIY-EFI list <diy_efi at diy-efi.org>
>Subject: CPU and hardware advice sought for EFI
>Date: Mon, 25 Feb 2002 13:21:46 -0800
>
>Hi All,
>
>I've been pondering this for a while and just thought I'd give in and just 
>do
>it.  I want a fully managed engine from a single embedded device doing
>everything to run a motor.
>
>Target engine(s):
>	Honda 700cc V4 water-cooled from a VF700S Sabre (development)
>	Volkswagen 2100cc Type-4 opposed 4, air cooled. (final, ~150 hp target)
>
>I have around 5 years experience doing application level C programming in a
>desktop environment -- mainly developer tool and scripting language 
>oriented
>with previous experience in electronic repair and design.  This is my first
>embedded/real-time device.  Sounds a whole lot more fun than silly 
>developer
>tools I do by day ;)
>
>A few weeks ago I was playing around with a Real Time Operating System 
>(RTOS)
>called MicroC/OS-II [ http://www.ucos-ii.com ] from the author's book.  
>Cool
>stuff, nice book, gosh I hate assembly...  A friend recommended I have a 
>look at
>QNX's Nutrino kernel [ http://www.qnx.com ].  It seems to be gaining 
>acceptance
>in automotive appliances.
>
>Designing is research.  `Search` being the predominant part of the word.  
>Here's
>what I found for a controller:
>
>http://www.tern.com/586e_data.htm
>http://www.tern.com/p50.htm
>http://www.tern.com/flashcore.htm
>
>SRAM is low, but execution code can run out of a flash card.  P-Mode?  
>cs:ds
>gives me a headache.  The p50 looks sweet with all that I/O.  I think my
>requirements would be the following:
>
>Inputs:
>	(2) lo-sample-rate ADC, cylinder head temp. 1 each side.
>	(1) lo-sample-rate ADC, oil temp.
>	(1) lo-sample-rate ADC, oil pressure.
>	(2) high-sample-rate ADC, knock sensors, 1 each side.
>	(1) lo-sample-rate ADC, throttle position sensor.
>	(2) lo-sample-rate ADC, manifold absolute pressure, 1 each side.
>	(2) lo-sample-rate ADC, exhaust O2 sensors, 1 each side.
>	(??) crankshaft/camshaft rotational position.
>
>Outputs:
>	(4) lo-side DIO, ignition coil amps for direct fire.
>	(4) lo-side DIO, injector drivers.
>	(2) lo-sample-rate DAC, servos or steppers for the cooling air flaps.
>	    (It's a VW engine, remember?)
>	(1) serial I/O to the dash for gauges.
>
>
>Could people comment on the above and help me fill in the gaps?  I'm rather
>overwhelmed, but having fun trying to spec a complete system from what 
>little I
>can work through.  I'm trying to prototype the FFT routines for the knock
>sensors, now.  Thanks.
>--
>David Gravereaux <davygrvy at pobox.com>
>[species: human; planet: earth,milkyway,alpha sector]
>Please be aware of the 7.5 year ping times when placing a call from alpha 
>centari
>
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