Old 486 Board for ECU??

[Mike from West Australia]

At 05:42 AM 2/5/2000 +0200, you wrote:

>> > Engine at 9000 rpm = 150 per second = dist 75 per second
>> > For a CAS with 360 deg pulses/rev thats 75*360 = 27KHz
>>
>> This gives you a base resolution of 37 microseconds. *Far* too coarse to
>run
>> any engine at low speed. Forget driveability and low emissions :)
>
>To emphasise the 'far too coarse' part, think that a system based on a crank
>interrupt every two degree as 'master clock', as you suggest, will result in
>a resolution as low as 333us per tick at 1000 rpm. This will probably result
>in very poor idle, in addition to the poor emission and driveability issues
>I've already mentionned.
>
>Also, two degrees resolution for spark timing is also too coarse to allow
>you to extract every bit of torque from a given engine.

Oh really - the CAS generates the int - you obviously wouldn't use
it as the clock - thats what the timers are for.

Why would oyu want to follow a negative line of reasoning when you have
a timer to do the job for you ;)

rgds

Mike

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