I think I am running into limitations of the MC68HC908.
I think I need another timer module for the dwell calcs.
Since I am doing another board anyway I am thinking putting a faster and better
processor on it.
Not much different in cost and some of the later Megasquirt asm programs will work.
The same processor is used on the daughter card. However there is other stuff on the
daughter card we don't need. GM stepper IAC control not needed. CANBus communications
for interface with GPIO Board, IO Extender, or other devices.
DIYautotune wants $199 for the daughter card but you still have to pay another $250
for the mother board.
Why not? Just a few extra bucks for the processor. $10 total roughly. You can never
have enough I/O. http://tinyurl.com/755wdzh
The MC9SC64 has no ROM in it. You flash the whole program in it.
It has 64K flash and 4K RAM.
Here is a list of feature.
-----------------------------------------------------------------------------------------
Freescale Semiconductor, Inc.
— Flexible identifier filter programmable as 2 x 32 bit, 4 x 16 bit or 8 x 8 bit
— Four separate interrupt channels for receive, transmit, error and wake-up
— Low-pass filter wake-up function
— Loop-back for self test operation
• Timer Module (TIM)
— 16-bit Counter with 7-bit Prescaler
— 8 programmable input capture or output compare channels
— Simple PWM Mode
— Modulo Reset of Timer Counter
— 16-Bit Pulse Accumulator
— External Event Counting
— Gated Time Accumulation
• 6 PWM channels
— Programmable period and duty cycle
— 8-bit 6-channel or 16-bit 3-channel
— Separate control for each pulse width and duty cycle
— Center-aligned or left-aligned outputs
— Programmable clock select logic with a wide range of frequencies
— Fast emergency shutdown input
• Serial interfaces
— One asynchronous serial communications interface (SCI)
— One synchronous serial peripheral interface (SPI)
• CRG (Clock Reset Generator Module)
— Windowed COP watchdog,
— Real time interrupt,
— Clock monitor,
— Clock generation
— Reset Generation
— Phase-locked loop clock frequency multiplier
— Limp home mode in absence of external clock
— Low power 0.5 to 16 MHz crystal oscillator reference clock
• Operation frequency
— 32MHz equivalent to 16MHz Bus Speed for single chip
— 32MHz equivalent to 16MHz Bus Speed in expanded bus modes
— Option: 50MHz equivalent to 25MHz Bus Speed
• Internal 2.5V Regulator
— Supports an input voltage range from 3.3V-10% to 5.5V
— Low power mode capability
— Includes low voltage reset (LVR) circuitry
— Includes low voltage interrupt (LVI) circuitry
• 48-Pin LQFP, 52-Pin LQFP or 80-Pin QFP package
— Up to 58 I/O lines with 5V input and drive capability
— Up to 2 dedicated 5V input only lines (IRQ, XIRQ)
— 5V A/D converter inputs and 5V I/O
• Development support
— Single-wire background debugTM mode (BDM)
— On-chip hardware breakpoints
— Enhanced DBG12 debug features
----------------------------------------------------
Paul Lamar
I'm for the better processor. Like you said, you can never have too
many I/O's... especially if you foresee integrating an EFIS, etc.
Josh
The software for that is already done. Both in the megasquirt and the PC.
Over the years a tremendous amount of work has been done. It pays to take advantage
of that.
Paul Lamar
G'day Paul, Josh
I 'm totally out to lunch when it comes to EFI but I have a few
points/questions
1. does an o2 sensor adjust the fuel to acheive clean burning ( to
pass smog laws) or does it just give us a reading? This may foil our
efforts to adjust AFR for lean burn and best power.
2. if the sensor is clogged by solid lead accumulation, perhaps we
could move the pick-up out of the direct airflow by placing it in a
recessed position or behind a shroud/deflector. this will still
analyze the exhaust but protect it from lead accretion.
So I thought I would search to see if I could find a lead safe O2
sensor and found this info. I reckon that this may mean more to you
Paul than I.
http://www.factorypro.com/dyno/dyno_ec997,eddycurrent,mc,dynamometer.html.
Also try the links at the bottom of the page.
Maybe if we used a TPS that would shift AFR to best power at wot and
best economy below 75%. Or perhaps different power maps as the race
boys use for power/economy modes. Back to you.
Graeme Riley
1. Usually the O2 sensor system are set to stoichiometric or about 14.7:1 air fuel
ratio. It depends on what kind of smog you are talking about. If you are talking
about NOx yes this gives a low smog number but at a severe fuel burn penalty. Lean
burn high NOs gives a better BSFC. Long story but here is a bit about it. B.
Bruce-Biggs. The War Against the Automobile. Dutton. 1977 book explains it the best.
Don't get me started :)
2. They might be one to something.
http://tinyurl.com/cps7v2o
Paul Lamar
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