AHHHHHHH!! What am i missing

S

sketchy

New Member
You guys must think i am well thick. I just dont get it. I think i am getting the hang of it so i read up and try somthing and it dose not work. BooHoo.

I Now have a problem with button code.

BUTTON pin,downstate,delay,rate,bytevariable,targetstate,address
- Pin is a variable/constant (0-7) which specifies the i/o pin to use.
- Downstate is a variable/constant (0 or 1) which specifies what logical state is
read when the button is pressed.
- Delay is a variable/constant (0-255) which specifies time before a repeat if
BUTTON is used within a loop.
- Rate is a variable/constant (0-255) which specifies the auto-repeat rate in
BUTTON cycles.
- Bytevariable is the workspace. It must be cleared to 0 before being used by
BUTTON for the first time.
- Targetstate is a variable/constant (0 or 1) which specifies what state (0=not
pressed, 1=pressed) the button should be in for a branch to occur.
- Address is a label which specifies where to go if the button is in the target
state.
Click to expand...
If understand what the manuel above says downstate should be 1 when the button is pressed and targetstate should be 1 when the button is pressed.

So why does the example code work when it is all set to 0
Code: 
main: button 0,0,200,100,b2,0,cont
‘ jump to cont unless pin0 = 0
toggle 1 ‘ else toggle input
goto main
cont:

b1=b1+1
goto main
What is the relevance of B2 as it dose not change in the simulator.

I have written this code
Code: 
main: button 0,1,50,50,b0,1,cont

goto main

cont:

b1=b1+1
goto main
and it works mor or less the same but both codes only work once.
If the button is pressed a second time the cycle stops on the button code line instead of jumping to cont.

What i want to do is make b1 cycle 0,1,2,3,0,1,2,3,etc every time the button is pressed so i can write a code that says somthing like if b1 = 1 then or if b1 = 2 then and so on

What am i missing or am i to thick to realise i am thick :)

Thanks again

Joe
 
S

sketchy

New Member
I think so. i am going to get an lm317 chip and a 3.9ohm resistor tommorw from rs cos i have one just down the road so fingers crossed it will work ok at 320ma.

i have not found out what a buck regulator is but i will look in to it .

thanks for the kspek link that was very good.
 
E

eclectic

Moderator
Joe.

Just out of interest.

LM317 and a 3.9 ohm resistor? Is that all?

Can you show us what circuit you are planning to use?

Or, the datasheet page?

e
 
B

BCJKiwi

Senior Member
This code from the last post (#7) in this thread
http://www.picaxeforum.co.uk/showthread.php?t=10139 (08M controlled Adjustable Voltage Regulator).
It may help? This was the first working Button command code I achieved. Had a couple of quick dabbles previously without success and this solution took more time than I would have expected to sort out so you are not alone in finding this command tricky to comprehend.

Code: 
#PICAXE 08M
setfreq M8
SYMBOL Up_PB     = 4            'Input4 PB Up
SYMBOL Dn_PB     = 3            'Input3 PB Dn
SYMBOL FeedBk    = 1            'ADC1   FeedBack
SYMBOL Gate      = 2            'In/Out2
High Gate                       'Drive Vout to minimum for safety!
SYMBOL Dn_Var    = b8           'Button Command Repeat storage variable
SYMBOL Up_Var    = b9           'Button Command Repeat storage variable
SYMBOL Set_Var   = w5
SYMBOL FeedBk_Var= w6
Set_Var = 1                     'Preset Program to Minimum Vout for safety
 
main:
' These Button Command explanatory notes courstesy of BeanieBots.
' "Delay" is how many times the command must be passed before it does the first repeat.
' "Rate" is how many times the command must be passed before it subsequent repeats.
' "Var" must be set to zero before the command is used (as explained in the manual) but 
'  that must be a once only setting. It must be done before you enter the loop which scans your button.
' Delay = 255 == No repeat
 
 
'BUTTON pin   ,downstate,delay,rate,bytevariable,targetstate,address
Button  Dn_PB ,1        ,200  ,4   ,Dn_Var      ,1          ,Vout_Dn  'Delay ~ Max = 254 = Longest 
Button  Up_PB ,1        ,200  ,4   ,Up_Var      ,1          ,Vout_Up  'Rate  ~ Min = 1   = Fastest

goto adjust      'If no button pressed, goto Adjust:
Vout_Dn:
   Set_Var = Set_Var - 1 Min 1  'If min not set at 1, 0-1=65535 ~ underflows Set_Var to 65535!
   goto Adjust
Vout_Up:
   Set_Var = Set_Var + 1 Max 1023
adjust:
   readadc10 FeedBk,FeedBk_Var  'get voltage data from output via 240R and Vout
   if Set_Var = FeedBk_Var then
      input Gate                'hold Gate charge
      goto  main                'return, output matches target
   EndIf
increase:
   if Set_Var > FeedBk_Var then 'Out put is too low so raise output
      low Gate                  'lower Gate V = Lower MOSFET R = Higher Current through Adj circuit = higher Vout
      goto main
   EndIf
decrease:
   'if Target < FeedBk_Var then ~ falls through to decrease if not increase! If...Endif not required
      high Gate                 'Higher Gate V = Higher MOSFET R = Lower Current through Adj circuit = Lower Vout
      goto main
end
 
Last edited:
B

BeanieBots

Moderator
eclectic said:
Joe.

Just out of interest.

LM317 and a 3.9 ohm resistor? Is that all?

Can you show us what circuit you are planning to use?

Or, the datasheet page?

e
Click to expand...
Yep, that's all you need.
Can be done with any regulator to create a constant current but the LM317 is the best because the voltage across the resistor is only 1.25v.
It can be done with a 7805 but that would require 5v across the resistor.
Keep an eye on the power dissipation though.
 
S

sketchy

New Member
when you say.

Keep an eye on the power dissipation though. do you mean heat?

Why is 1.25v better. I thought this way was just to limit the current so the output voltage is the same as the supply voltage?

joe
 
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