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Forum Index : Microcontroller and PC projects : Interrupt Issue
| Author | Message | ||||
jman Guru  Joined: 12/06/2011 Location: New ZealandPosts: 711 |
Hi Please take a look at the code below the issue is that when the SetTick command is run from an interrupt it does not work. If I run the settick command directly or before an interrupt it works as expected. What am I missing or is there a bug in the firmware This is with a 44Pin MX170 MM v5.1 SetPin 8, Din SetPin 9, Din Main: If Pin(8) = 0 Then GoTo TickTest If Pin(9) = 0 Then GoTo ITest GoTo Main ITest: Temp=0:Print "Interupt Loop" SetPin 36, IntL, TickTest Do Loop End TickTest: Temp=0:Print "Got Here" SetPin 36, Off SetTick 300, OutInt, 2 'This does NOT run from Interrupt Do While Temp < 10 Print Temp Loop SetTick 0, 0, 2 End '============================================== OutInt: If OutC = 1 Then OutC=0 : IReturn EndIf OutC=1 : Temp=Temp+1 IReturn '============================================== Many Thanks Jman |
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| PicFan Senior Member  Joined: 18/03/2014 Location: AustriaPosts: 133 |
I think that is a problem with the Interrupt priority, the SETTICK have the lowest priority ? Also i think it is not good a "do while" loop in a Interruptroutine ? |
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| JohnS Guru Joined: 18/11/2011 Location: United KingdomPosts: 3668 |
I hope that's deliberately contrived (and horrid) code. You want to keep any interrupt short. Preferably no PRINTs, too. If you turn it into a more sane sample - which may be longer - does it then work? If not, post it. Yo might like to avoid IReturn and use a SUB in every case. Right now you even have TickTest apparently for an interrupt but no IReturn. It's not going to end well!! John |
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Geoffg Guru Joined: 06/06/2011 Location: AustraliaPosts: 3165 |
There is nothing in the SETTICK command that would stop it from running correctly from within an interrupt. It just sets up the relevant registers and exits. I suspect that it is something within your code. EDIT: I think that I can see the problem. You run SETTICK from within an interrupt and your code will only exit this interrupt when the SETTICK interrupt has been called 10 times. But MMBasic will not service the SETTICK interrupt because it is already within an interrupt - you will never receive an interrupt within an interrupt. Geoff Geoff Graham - http://geoffg.net |
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| jman Guru Joined: 12/06/2011 Location: New ZealandPosts: 711 |
Hi Ok so JohnS did not like the test code yes it was just test code. Please see below and hopefully this is a better explanation It seems that the SetTick command does not start until after the interrupt routine has exited. The code below uses SetTick then a pause at the start to prove SetTick works during a pause With the Interrupt routine the SetTick only starts after the pause (ie the IReturn) Hopefully this explains it a bit better Regards Jman SetTick 500, OutInt, 2 Pause 5000 Print "Pause end" SetTick 0, 0, 2 SetPin 8, Din SetPin 36, INTL, ITest Main: If Pin(8) = 0 Then GoSub TickTest GoTo Main TickTest: Print "Got Here from Button 1" SetTick 500, OutInt, 2 Pause 5000 Return ITest: Print "Got Here from Interrupt" SetPin 36, Off SetTick 500, OutInt, 2 Pause 5000 IReturn '============================================== Sub OutInt Print "Got here OutInt " End Sub '============================================== |
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BobD Guru Joined: 07/12/2011 Location: AustraliaPosts: 935 |
jman If I recall correctly, somewhere in the older manuals and maybe in the more recent ones, there used to be a listing of interrupt priorities. Also noted was that lower priority interrupts were masked off while a higher (or any?) interrupt was in progress. Also mentioned was that interrupts are not hardware but software and are processed at the end of the current instruction unless masked. If I'm correct, would that make sense of your problem? It's too early in the morning for me to try analysis on it and we won at cricket  and we didn't even have to bowl underarm. 
Bob |
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| jman Guru Joined: 12/06/2011 Location: New ZealandPosts: 711 |
So right you are from the manual page 40 "During the processing of an interrupt all other interrupts are disabled until the interrupt subroutine returns." Great so now I know Thanks for the help Regards Jman |
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