12F683 and DT Instant Interrupts

[jderson]

I am trying to use Darrel Taylor's great Instant Interrupts (thank you!) on a 12F part. Originally, I was using a 12F635. I changed to a 12F683 after reading posts about doing this, because I was under the impression it would work O.K. However, I still get the following message when compiling:

ERROR:Variable wsave2 position request 288 beyond RAM_END 191.

Do I still need to comment out some lines?

@ device pic12f683, INTRC_OSC_NOCLKOUT, WDT_OFF, MCLR_OFF, PROTECT_OFF

OPTION_REG = %11000000
OSCCON = %01100001
TRISIO = %001100
CMCON0 = %00000111
ANSEL = 0
CCP1CON = 0


RATESW VAR BYTE

HIGH GPIO.0
HIGH GPIO.1
HIGH GPIO.4
HIGH GPIO.5
pause 100

RATESW = 0

INCLUDE "DT_INTS-14.bas" ' Base Interrupt System

ASM
INT_LIST macro ; IntSource, Label, Type, ResetFlag?
INT_Handler INT_INT, _SWINT, PBP, yes
endm
INT_CREATE ; Creates the interrupt processor

INT_ENABLE INT_INT ; enable external (INT) interrupts
ENDASM

Main:

if ratesw = 1 then Rate1
if ratesw = 2 then rate2
if ratesw = 3 then rate3
if RATESW > 3 then RESET
GOTO Main

Rate1:

while ratesw = 1
LOW GPIO.0
low GPIO.1
pause 150
high GPIO.0
high GPIO.1
low GPIO.4
low GPIO.5
PAUSE 150
high GPIO.4
high GPIO.5
wend

Rate2:

while ratesw = 2
LOW GPIO.0
low GPIO.1
pause 100
high GPIO.0
high GPIO.1
low GPIO.4
low GPIO.5
PAUSE 100
high GPIO.4
high GPIO.5
wend

Rate3:

while ratesw = 3
LOW GPIO.0
low GPIO.1
pause 50
high GPIO.0
high GPIO.1
low GPIO.4
low GPIO.5
PAUSE 50
high GPIO.4
high GPIO.5
wend



RESET:

RATESW = 0
GOTO Main

GOTO Main

'---[INT - interrupt handler]---------------------------------------------------
SWINT:

while GPIO.2 = 0:wend
pause 100
if GPIO.2 = 1 then
RATESW = RATESW + 1
endif

@ INT_RETURN


Thank you

[mister_e]

Yes, open DT_INTS-14.bas file.. and at the top, you'll discover...

' --- IF any of these three lines cause an error ?? ----------------------------
' Comment them out to fix the problem ----
' -- It depends on which Chip you are using, as to which variables are needed --
wsave1 var byte $A0 SYSTEM ' location for W if in bank1
wsave2 var byte $120 SYSTEM ' location for W if in bank2
wsave3 var byte $1A0 SYSTEM ' location for W if in bank3
' ------------------------------------------------------------------------------

[jderson]

Thank you for the reply. Unfortunately, I have all three lines commented out and now I get "Unable to fit wsave" .

[Darrel Taylor]

From that error, it looks like you're still compiling for the 12F635.

If using MicroCode Studio, make sure the device dropdown box says 12F683.

For the 683, you'll need both wsave and wsave1.

Or you can use the alternate wsave location $70, and comment the other 3.
<br>

[jderson]

Thank you Darrel. Yes , the drop-down was incorrect. The program doesn't work, but that's because it's still Halloween!

[mr.sneezy]

I'm trying to get my head across the DT Interrupt code for a small new RC modeling project and I'm trying a test example first (the blinky LED) , compiling with MCS. I have 12f683 selected in MCS and MPASM being used.

but I get an odd warning message from MCS thus :
Warning[219] d:\pbp code\pbp\pbppic14.lib 336 : Invalid RAM location specified
Warning[219] d:\pbp code\pbp\pbppic14.lib 892 : Invalid RAM location specified

Anybody know why and if I should just disregard it ?

I commented out the wsave lines as required (which led me here BTW)

My code


LED1 VAR PORTB.1

INCLUDE "DT_INTS-14.bas" ' Base Interrupt System
INCLUDE "ReEnterPBP.bas" ' Include if using PBP interrupts

ASM
RBIF = GPIF
RBIE = GPIE

INT_LIST macro ; IntSource, Label, Type, ResetFlag?
INT_Handler TMR1_INT, _ToggleLED1, PBP, yes
endm
INT_CREATE ; Creates the interrupt processor
ENDASM

T1CON = $31 ; Prescaler = 8, TMR1ON
@ INT_ENABLE TMR1_INT ; enable Timer 1 interrupts

Main:
PAUSE 1
GOTO Main

'---[TMR1 - interrupt handler]--------------------------------------------------
ToggleLED1:
TOGGLE LED1
@ INT_RETURN

My project is quite simple. A 22.5mS interrupt timer (TMR1 I guess) and toggle a few pins then wait for the next interrupt.
Martin

[Darrel Taylor]

Try ...

;LED1 VAR PORTB.1

LED1 VAR GPIO.1
<br>

[mr.sneezy]

Try ...

;LED1 VAR PORTB.1

LED1 VAR GPIO.1
<br>

Yeah.... I forgot about port pins on the smaller PIC's (again).
Ta, Martin

[mr.sneezy]

Now my code compiles fine thankyou, barring a overwriting previous address warning from my config settings (I understand why that is). But I have a small question regarding reloading the timer for anyone.

Must I stop the timer while reloading it with a hex value of A823 in the interrupt handler code (which is all it needs to do) ?

T1CON = %0
TMR1H = $A8
TMR1L = $23
T1CON = %1

Or can I ignore the stop-start safely. Given I can tweak the timer value by trial and error to get my 22.5mS @ 4Mhz ?

The only examples I've dug out on the forum are using ASM code and I'm not strong on interpreting it.

[Darrel Taylor]

It's not absolutely required, unless the reload value is calculated.

When you have a fixed value like that, you can be pretty sure the LowByte won't overflow before it loads the HighByte.

However, you'll need to load the LowByte first, if you're not turning the timer off. And you'll also need to subtract 7 from the number you have, which is adjusted for a reload that does turn the timer off.
<br>

[mr.sneezy]

In my code I do a bunch of stuff then wait doing nothing for an interrupt some mS later, then when that happens I want to run my bunch of stuff again, forever and ever. Rather than return to where the interrupt occurred in my 'wait doing nothing'....

I see the obvious way is to put my 'bunch of stuff code in the interrupt handler subroutine, but that makes the int handler routine very big and the 'main' code very small. Looks all wrong to me. Is that the way to do it or is there a proper way to get the int handler to go to my 'bunch of stuff' rather than return to where it was interrupted from ?


LED1 VAR GPIO.1

INCLUDE "DT_INTS-14.bas" ' Base Interrupt System
INCLUDE "ReEnterPBP.bas" ' Include if using PBP interrupts

ASM
INT_LIST macro ; IntSource, Label, Type, ResetFlag?
INT_Handler TMR1_INT, _ToggleLED1, PBP, yes
endm
INT_CREATE ; Creates the interrupt processor
ENDASM

T1CON = $01 ; Prescaler = 1, TMR1ON
@ INT_ENABLE TMR1_INT ; enable Timer 1 interrupts

Main:
Big bunch of stuff

wait_here:
pause 1
Goto wait_here 'wait for an interrupt here
(Return from Interrupt would hang here ?)

GOTO Main 'should never happen

'---[TMR1 - interrupt handler]--------------------------------------------------
ToggleLED1:

T1CON = %0
TMR1L = $23
TMR1H = $A8
T1CON = %1
TOGGLE LED1
@ INT_RETURN

[Acetronics2]

Hi, Mr Sneezy

I do not know what's your final project ... BUT :

Did you ever considered the R/C Framerate is an excellent timebase with 22.5 ms granularity ??? ( looks Graupner/JR remote ??? )

No need for heavy interrupt implementing, then.

just a simple idea ...

Alain

[mr.sneezy]

Hi, Mr Sneezy

I do not know what's your final project ... BUT :

Alain

but you're very very close Alain.....

Except in my application I'm needing to generate an 8ch PPM pulse frame at 22.5mS rate from scratch.

To cut to the chase what I want to do is build a simple RC TX radio eliminator so I can test prototype 2.4Ghz transmitter modules in the field (range tests etc etc) without needing a second person to wiggle the sticks on the radio (it uses Futaba compatible TX modules). I did the obvious thing and looked for existing projects but they all seem to decode PPM frames not create them...

The app will change the PPM period for two channels (at least) slowly so the servos move at the RX end while I move away doing testing (sometimes Km's). The remaining channels will just be 1.5mS center position all the time.

Sorry for the apparently newbie programming questions, I've actually written some quite large complex code in the past (way way past) but I do it so infrequently now I have to go back to basics at the start of a new project like a beginner. I never seem to do a similar project twice which doesn't help.

I guess another way of asking my question is can I have a lot of code in the interrupt handler subroutine ? Or could that bugger up the interrupt code ?

Thanks,
Martin

[Acetronics2]

Hi, Martin

I already have it here aboard a 12F675 ... just change repeating time to match the 22.5 ms ( was originally intended for a MPX frame ) lol !!!

But do no want to tear your pleasure at all ... if it's your wish to discover interrupt charms !

I' d recommand you to trim the first channel to 1.1 ms, the second to 1.2, third to 1.3 ... and so on. That will make later channel identification much easier.

My application was static demo of boats without using RF ... ( Other Boats on "live show" at same time ... for the Warwick show !).

Humouristically yours ...

Alain

[Acetronics2]

BTW ...

I remember there's a non-PCM other solution ...

PULSIN + some little lines can detect bad pulse duration ( = glitches = max. range) just place a servo in a preset position if glitches appear ( you can allow as much glitches as you want before entering " Fail safe" )

Based on that ... you just take a receiver a batt and a servo, or your plane ... with you while the Tx keeps steady.

I use it aboard a Glo Driver : Engine is slammed to idle, or cut, if too much glitches.

Already saved many planes ... including scale championship ones !!!


PCM have that feature ... so, just need to use it !!!

My MC18 Transmitter also has a Servo-test feature ... that move automatically servos one after the other ...


I didn't write it ... but why not use the coder's signal through the "Pupil's plug" ???
Alain

[mr.sneezy]

Hi, Martin

I already have it here aboard a 12F675 ... just change repeating time to match the 22.5 ms ( was originally intended for a MPX frame ) lol !!!

Alain

Hi Alain,

Yes thanks, if you have a code that does the same job I'd like to see it. I'll either try it out as you wrote it or use it for inspiration to finish mine. You could send it via a personal message or post it here. I have a couple of 12F675's in my bits box.

Going on to your second reply, that is a good idea about the servo positions. To take it one step further I could have a PIC analysing the channel outputs over time and coming up with a sort of 'error rate' like we use on digital communications bearers here. Going all the way would have a PIC with LCD, displaying error rate (glitches/holds per minute ?) for each channel plus a summed figure. That way I can compare different 2.4Ghz receiver versions against a mathmatical benchmark...

Oh boy, I'd better go do something else before this turns into a monster project !

Martin

[mr.sneezy]

Getting back on topic with DT int code. Is it a bad thing to put GOTO's or GOSUB'S inside the interrupt handler ? Therefore maybe never seeing the @ INT_RETURN

'---[TMR1 - interrupt handler]--------------------------------------------------
ToggleLED1:

T1CON = %0
TMR1L = $23
TMR1H = $A8
T1CON = %1
TOGGLE LED1

GOTO MAIN 'is this dangerous ?

@ INT_RETURN

[Darrel Taylor]

GOTO MAIN 'is this dangerous ?
Suicidal!

You will only get one interrupt that way, untill power is cycled or the GIE bit is set manually.

If you need to trigger processes in the main loop, you can set a Flag in the handler. Once it returns from the handler, the main loop can execute the required task where it can be interrupted again.

On 12F's and 16F's, you should NEVER gosub from the handler. There just aren't enough stack levels.

[mr.sneezy]

"Suicidal" I like it Darrel :-)
That word doesn't get used in code discussion much I'm sure...
OK, I just hit 'undo' on my code several times to stop myself needing to go slash my wrists ;-)

Flag. OK, if I understand correct I should set a flag variable in the int handler, then put my main code into a tight loop checking for it, then jump to my PPM output code when true, then back to the tight loop after clearing the flag...

There are a heap of ways to make a tight loop (If-then, While-wend, repeat-until). What would be the tightest (fastest) ? ASM ?

Martin

[Darrel Taylor]

There are a heap of ways to make a tight loop (If-then, While-wend, repeat-until). What would be the tightest (fastest) ? ASM ?
Anything that requires precise timing should be done in the handler, preferably in an ASM handler.

When it returns to the Main loop with a Flag set, the process it triggers should be able to do it, "whenever it gets around to it". There may be several things going on, and there's no guarantee when it will be processed.

If you're reading servo pulses, then the entire process of measuring the pulse should be done with the interrupts, and I don't mean sitting in a PULSIN statement in the handler. On the rising edge, start a timer. On the falling edge, stop the timer and collect the reading. Each time leaving the handler until the next condition occurs. Once you have a reading, then set a flag to let the main loop know to process the data. Now it has all the time in-between pulses to work on all those error rates, jitter etc and display them on the LCD at it's leisure.

[mr.sneezy]

Thanks Darrel,
In this part of the project (maybe the only part) I'm making the pulses, eight in a row for eight RC servo channels, of varying periods, rather than reading them. The TMR1 interrupt is just keeping the overall frame timing right.
Looking it now I think a tight loop reading the roll-over flag of the counter then doing the pulse train code would have worked just as well. I guess I thought that a real timer interrupt would minimise jitter in the total frame length.
Never mind, I'll carry on with the interrupt method now that I've started it.

I'd still like to see Alains code though.... Alain ?

Martin

[Acetronics2]

Hi, Martin

Darrel will love it, for sure !!! ( Lol ...)



'************************************************* ****************************
'FRAMEGEN.BAS
'************************************************* ****************************
'
' Générateur de Trame R/C Graupner/Multiplex sur 12F675
'
' 4,7,8 ou 9 Canaux - Neutre 1.5 ms
'
' Oscillateur interne 4 Mhz
'
' Trames déclenchées par interruptions TMR0 : PS = 1/128 Pl = 80
'
' Sortie sur GPIO.5
' Choix 4,7,8 ou 9 voies sur GPIO.3 et 4

'************************************************* ****************************
'************************************************* ****************************
'
@ __config _INTRC_OSC_NOCLKOUT & _WDT_ON & _PWRTE_ON & _MCLRE_OFF & _CP_OFF & _BODEN_ON


DEFINE OSC 4
DEFINE OSCCAL_1K 1
DEFINE INTHAND _Marker

ADCON0 = 0
ANSEL = 0
CMCON = 7

OPTION_REG = %10000110 'Disable Pull-Ups - PSA = 128
INTCON = %00100000 'TMR0 interrupt
PIE1 = 0
PIR1 = 0

'************************************************* ****************************
' Constantes

Mark CON 400
Reload CON 80
Neutral CON 1500
GR CON 8
MPX CON 9

'************************************************* ****************************
' Variables


PROGRAM var byte
PROGRAMOLD var byte

FRAME4 var bit
FRAME7 var bit
FRAME8 var bit

CLEAR

'************************************************* ****************************
' I/Os

GPIO =%00100000 'GPIO.5 = 1 at startup
TRISIO =%00011000 'set GPIO3 GPIO4 as input GPIO.5 as Output

'************************************************* ****************************

GOTO INIT

'************************************************* ****************************
'************************************************* ****************************
Marker: ' Interruption - Génération de la trame

TMR0 = Reload

GPIO.5 = 0
PAUSEUS Mark

GPIO.5 = 1 ' Voie 1
PAUSEUS 696

GPIO.5 = 0
PAUSEUS Mark

GPIO.5 = 1 ' Voie 2
PAUSEUS 796

GPIO.5 = 0
PAUSEUS Mark

GPIO.5 = 1 ' Voie 3
PAUSEUS 896

GPIO.5 = 0
PAUSEUS Mark

GPIO.5 = 1 ' Voie 4
PAUSEUS 992

IF FRAME4 THEN Selection

@ NOP
GPIO.5 = 0
PAUSEUS Mark

GPIO.5 = 1 ' Voie 5 - 1500µS
PAUSEUS 1096

GPIO.5 = 0
PAUSEUS Mark

GPIO.5 = 1 ' Voie 6
PAUSEUS 1196

GPIO.5 = 0
PAUSEUS Mark

GPIO.5 = 1 ' Voie 7
PAUSEUS 1290

IF FRAME7 THEN Selection

@ NOP
GPIO.5 = 0
PAUSEUS Mark

GPIO.5 = 1 ' Voie 8
PAUSEUS 1392

IF FRAME8 THEN Selection

@ NOP
GPIO.5 = 0
PAUSEUS Mark

GPIO.5 = 1 ' Voie 9
PAUSEUS 1496

Selection:

GPIO.5 = 0
PAUSEUS Mark

GPIO.5 = 1

'************************************************* ****************************
'Lecture des Jumpers

PROGRAM = GPIO & %00011000

IF PROGRAMOLD <> PROGRAM THEN INIT

'************************************************* ****************************
Start: 'Fin d'Interruption

INTCON.2 = 0
INTCON.7 = 1

'************************************************* ****************************
CYCLE: 'Boucle de fonctionnement

WHILE 1
WEND

'************************************************* ****************************
INIT: 'Lecture des Jumpers

PROGRAM = GPIO & %00011000

SELECT CASE Program

CASE 24

FRAME4 = 1 : FRAME7 = 0 : FRAME8 = 0

CASE 16

FRAME4 = 0 : FRAME7 = 1 : FRAME8 = 0

CASE 8

FRAME4 = 0 : FRAME7 = 0 : FRAME8 = 1

CASE ELSE

FRAME4 = 0 : FRAME7 = 0 : FRAME8 = 0

END SELECT

PROGRAMOLD = PROGRAM

GOTO Start

END



If you want to have variable pulse length... just inc or dec the PAUSEUS value before the "START" Label


And ... if you find something strange ... it is NOT an error !!!

( I told you Darrel would love it ....)

Alain

[Darrel Taylor]

Love comes in many forms ...

I'm still looking for the one that applies here. :p

Ummm, I found something strange ...
<br>

[Acetronics2]

Love comes in many forms ...

I'm still looking for the one that applies here. :p

Ummm, I found something strange ...
<br>

Hi, Darrel,

Really ???

I'm so surprised ... Something missing, may be ???

Regards
Alain

[mister_e]

1)French comments.
2)No DT-int
3)Mix ASM INT asm PBP... no context save/restore (even if probably not needed)
DEFINE INTHAND _Marker
'
'
'
'
Marker: ' Interruption - Génération de la trame

Have i said rusty rusty KeyWee? :D

[Acetronics2]

Hi, Steve

I love this kind of programs ...

Everybody looks for the failure ... and there's no failure.

Just some "far from the manual" tricks ...

Point 1 ) ... "Babelfish" it !!! as I didn't think one day it had to go out of my PC !!!
Point 2 ) Why use DT interrupts ??? 1K prog memory and overall RAM will be MUCH too short ... ( Lol )
Point 3 ) ABSOLUTELY Nothing to save here ... why loose time and hair ???

Have a look to the produced .asm ... that's the important thing ... nooooooo ???

Ha,ha ... maudit Français, hein ???

best regards
Alain

[mr.sneezy]

I thought I might post my first working cut. It creates an 8ch PPM frame. The first two channels step in opposition to each other. The device allows me to run tests on manufacturers transmitter modules without using a real RC transmitter or operator.

I enhanced it after this for different speeds and button control


'************************************************* ***************
'* Name : 8ch PPM generator.BAS
'* Author : Martin S (mr.sneezy)
'* Notice : Copyright (c) 2008 [select VIEW...EDITOR OPTIONS]
'* : All Rights Reserved
'* Date : 22/11/2008
'* Version : 1.0
'* Notes : Code for PIC12F683, logic direction suits Futaba compatible TX modules
'* :
'************************************************* ***************
Define Osc 4

' Software Defines
' ----------------
Temp_Var2 var word
Servo_dir var byte ' Store the servo going left or right direction flag 0 or 1
Run_flag var byte 'Loop flag for triggering a PPM frame
PPM1_value var Word 'variable for the value ch1 servo position pulse
PPM2_value var Word 'variable for the value ch2 servo position pulse

PPM_Out Var GPIO.0 'PPM drive for TX module is on this port pin
LED1 Var GPIO.1 'Indicator LED is on this port pin


' Initialise Processor - check for each PIC type
' --------------------
VRCON.7 = %0 'Comparator voltage reference OFF
CMCON0 = %111 'Comparator inputs to OFF, all pins normal I/O
ANSEL = 0 'Turn off all AD's

' Set GPIO port pins as Input or Output
TRISIO.0 = 0 'Input(0 = output, 1 = Input)
TRISIO.1 = 0 '
TRISIO.2 = 0 '
TRISIO.3 = 1 '
TRISIO.5 = 1 '
TRISIO.6 = 1 '

INCLUDE "DT_INTS-14.bas" ' Base Interrupt System
INCLUDE "ReEnterPBP.bas" ' Include if using PBP interrupts

ASM
INT_LIST macro ; IntSource, Label, Type, ResetFlag?
INT_Handler TMR1_INT, _my_handler, PBP, yes
endm
INT_CREATE ; Creates the interrupt processor
ENDASM

T1CON = $1 ; TMR1ON
@ INT_ENABLE TMR1_INT ; enable Timer 1 interrupts

Low LED1
Low PPM_out
PPM1_value = 500 'seed the center value of the servos
PPM2_value = 500 'seed the center value of the servos
Servo_dir = 0 'Set initial servo direction

Main:
While Run_flag = 0 'loop looking for trigger
goto Main
Wend

Gosub Start_pulse 'start of a channel (or sync pulse)
Gosub Channel_1 'channel 1 PPM period
Gosub Start_pulse 'start of a channel
Gosub Channel_2 'channel 2 PPM period
Gosub Unused_ch 'a complete PPM channel pulse set, servo centered (1500uS)
Gosub Unused_ch '
Gosub Unused_ch '
Gosub Unused_ch '
Gosub Unused_ch '
Gosub Unused_ch '
Gosub Start_pulse 'start of sync pulse

If Servo_dir = 0 then 'do math while waiting for interrupt, plenty of time
PPM1_value = PPM1_value + 5 'count upwards ch1 servo goes clockwise
Else
PPM1_value = PPM1_value - 5 'count downwards ch1 servo goes anti-clockwise
Endif

If PPM1_value = 1000 then 'detect servo limit CW
Servo_dir = 1
Endif

If PPM1_value = 0 then 'detect servo limit CCW
Servo_dir = 0
Endif

PPM2_value = 1000 - PPM1_value 'Ch2 servo moves opposite direction to servo Ch1

Run_flag = 0 'clear the interrupt handlers trigger flag
GOTO Main


Start_pulse:
high PPM_out
Pauseus 400 'channel start high period
Low PPM_out
return

Unused_ch:
high PPM_out
Pauseus 400 'channel start high period
Low PPM_out
Pauseus 1100 'Unused channel low period
return

Channel_1:
Pauseus PPM1_value 'just leave channel low for X time
Pauseus 600 'make up the minimum pulse to 1000uS
return

Channel_2:
Pauseus PPM2_value 'just leave channel low for X time
Pauseus 600 'make up the minimum pulse to 1000uS (start pluse + possition + this)
return


'---[TMR1 - interrupt handler]--------------------------------------------------
my_handler:

T1CON = %0 'Stop timer 1
TMR1L = $23 'Load for 22.5mS interrupts
TMR1H = $A8
T1CON = %1 'Start timer1
TOGGLE LED1

Run_flag = 1

@ INT_RETURN