Picaxe 41X1

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Jony_BC

Member
hi there guys. I was wondering were i can find/buy the picaxe 41X2. couse i think i saw somewere that only that one can run at 40 mhz, and correct me if im rong at any point please. i read that i got to put a resonator that is * by 4 jus like 10 * 4 = 40, no sure couse i don´t remender were did i read this. if you coul redirect something that could help me... and if someone could telme if the picaxe run well at 40 mhz and +/- how many instructions coul´d it make per second.:confused::confused:

sorry for my words i know there are not the best. and also my questions. (noob here:p)

thanks for all guys... :cool:
 
J

Jony_BC

Member
TKS

Sorry i´m not sure if i understud, So theres no picaxe 40X2 i read somewere not sure were sorry that the speed is overcloked whit the external resonator multiplied by the internal. Sorry i justa don´t remember.:( But anyway. i got a project to make, that is a electronic Ignicion. that as to made the advance of the spark in the program itself. and my big problem is that i figuerout the program, and at first I think the program was my onli problem but, the project its meant to work. at its for a two stroke engine that runs at a top 15000 Rpm MAx
and at top speed i realy don´t know i can count on picaxe only at 8 Mhz or even at 20 Mhz. So could you tel´me if the pic microprocessor whitout the picaxe in it can run faster? and how much it will cost me? And and programing itself its a lot diferente? bether i hope.:confused:

Thaks for your time. :)
 
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Jony_BC

Member
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sorry mate i tried to find it again but the only thing i found its the maximun speed of all the picaxe in a table :(. But if i manage to get it again:). i put it here. but could you help me whit my project? i just need to get some processor that in about 4 ms it can make a 60 or 50 comands maybe less. whit a few I2c comands a an interrupt in the midle.:confused:

Tks
 
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BeanieBots

Moderator
At 4Mhz each command typically takes 250uS.
I2C read/writes depends on the memory used so you will have to supply more details.
Only the X series support I2C.
The 28X1 can be clocked at 20Mhz but anything other than a multiple of 4Mhz is going to bring its own set of problems.
Is this for a car?
 
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Jony_BC

Member
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Yeah i´m aware. just was hoping that the picaxe could run 10 times faster as 40 mhz. no its for a motorbike engine(moped) :p its a two stroke engine so in one revolucion of the motor i need to get the picaxe to calculate the ignicion advance angle. and ignicion time. i´m using another picaxe to read the RPM and to Ic2out it. then the sensor its a a 40º angle before the uper stage of the piston. so to make a 20º adanve i calculate the time that the make need to move 1º then multiplied buy the advance angle then from that i make a pause. that i´m having also a problem with it couse the pause comand only goes to ms am i right? but thats another story. the conclusion is i have a engine that makes a 15000 in the red line. so i got maybe a 4 ms window to make all the code. runing and testing.I just told my teacher that i could limit the RPM of the engine for just 6000. but thats no good for me. i wantit to go to the end. and put a bike roling with a system made by me. i wanst thinkinh on start learning another programing and another tipe of microprocessor. but if just the only way...
 
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BeanieBots

Moderator
I think you will need PIC assembler to do what you want.
Interpreted BASIC will be too slow. A good BASIC assembler might be OK but that is not how PICAXE works.

Maybe someone else has some ideas for you.
 
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Jony_BC

Member
...

Yea i was thinking of that it was the next stepi wanted to make i think the programar its a lot expensive comapring to the picaxe. but a lot of the aplication that i wanted to do its for the auto area so i need a micro that is fast. do you know how much faster does they run? any good tuturials were to start were to buy? thanks for all the help man...
 
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MartinM57

Moderator
You will need a circa 20-40Mhz processor, running at 10-20MIPS, very tight assembly code programming, lookup tables to avoid mathematical calculations (there just isn't enough time to do them accurately enough via code) and a very good understanding of timers and interrupts (and ignition theory to understand about dwell times in coils etc) to achieve this.

Is this your first project and something you are hoping to get marks for at school? If so, I think it will be very hard for you and maybe you could look for something simpler?

By the way:
- you need to turn OFF the coil current at the time (angle) you want the spark to occur....which is only half the story, as you also need to turn it ON at some time. When will you do that?
-your sensor needs to be much further back from TDC than 40 degrees. Most existing systems have their sensors at least 90 BTDC to give you time to do the calculations at higher rpms
 
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Jony_BC

Member
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1º yes i´m a litle nooby in this area of programing. Yes its for my final project of the school. i don´t realy need much moore couse i get the best grade of my classe. I already achive that. I only got a litle information about the ingnicion i know all the basis since i´m learning to be a mecanic and eletrician auto n my school. But all that fisiq and mahts i only tried to thnk of them in the rihgt time thats the only way to not get desinteristet and still manage to like the math and fisiq lol. but thats just me. I already made some projects that my teacher give to us. all of them. so thats way my teacher give this project to me.
but just like id sayd i will like to push it further. i think i just found a nice person to ask something in this area. you seem to know what u are talking about. But in this case i don´t wan´t a lot of help couse i need to made it myself. But i acept all the information you could give me about the pic and assembler code. some PDF like the picaxe have for the comands will be great... But i think i will try do get the engine working with my 21X1 firts at a 6000 rpm max then go further. just to securo my grade we never know... and also my school to buy the programer and the pics will take years lol is a portuguese school run buy germans. so you could imagine eu portuguese first buy then think. they think, then think, and then maybe theyl buy. wel thats maybe way their big and we small. but who cares we have to be diferente. or else we couln´d lagh about eachother. ;) and life woldn´t bee all that funny
 
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Jony_BC

Member
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suite.

just what i was loking for a time ago. but a litle disapointed. I was hoping that the normal cdi diden´t came with ignicio advance. so i´m not doing nothing that will turn the motor with better performance. so it will only get worst or the same. Or i´m i thinking it rong the link you give is from someone project and the normal cdi don´t came whit adance??
 
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Charliem

Senior Member
Hi Jony_BC,

It does have advance.There is a excell spread sheet to figure the delay needed.So you can change it to suit your needs.
 
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