Just want to make sure this code doesn't fry my board before i try it

noobmuncher · 2009-12-26 03:58

I just pulled apart a Christmas present of pass which is an old "RAD Robot" I have. I am using a SN754410 Quad Half H-Bridge IC www.sparkfun.com/commerce/product_info.php?products_id=315 to power the opening and closing of the arms and the leaning forward and backwards of the torso. So I have it wired up to my propeller education kit via the pin layout described here www.hobbyengineering.com/appHBridge1A.html however I am really afraid of frying it with the code I have. I have hooked this up on the BS2 before and it worked fine, but with that I just told two of the 4 signal pins to send HIGH commands and the others to have LOW and then just changed it. With the propeller I am a bit confused by the dira and the outa commands. I just need pins 27 and 25 to receive HIGH while 24 and 26 LOW and conversely.

If some one can help with this very simple problem that would be great, I am just afraid of having something get fried ha ha.

Thanks!

Clock Loop · 2009-12-26 06:11

The chip you mention has recommended operating conditions of at least 4.5v.

noobmuncher · 2009-12-26 06:28

I thought the datasheet said that it's minimum HIGH was 2.5 or am I totally mistaken? Can this be remedied?

StefanL38 · 2009-12-26 06:47

Hello noobmuncher,

as you didn't attached your code I can only say a little

DIRA is to set the DIRection of an IO-Pin

  DIRA[noparse][[/noparse] 0 ] := 0 'set IO-PIN Number 0 as input
  DIRA[noparse][[/noparse] 0 ] := 1 'set IO-PIN Number 0 as output

  DIRA[noparse][[/noparse] 27 ] := 0 'set IO-PIN Number 27 as input
  DIRA[noparse][[/noparse] 27 ] := 1 'set IO-PIN Number 27 as output

OUTA is for setting the IO-pins voltage

  OUTA[noparse][[/noparse] 27 ] := 0 'set voltage on IO-Pin number 27 to 0.0V 
  OUTA[noparse][[/noparse] 27 ] := 1 'set voltage on IO-Pin number 27 to 3.3V

I enjoyed porting the BS2-example-code to SPIN

{BS2-Code:
MotorID VAR Byte        ' Current Motor ID
}
'ported to SPIN
'see lines with PUB MotorBrake(MotorID), PUB MotorReverse(MotorID) etc. 

CON
{BS2-code:
Motor1  CON 1           ' Motor 1 control on stamp pins 1, 3 and 5
                        ' SN754410 pins 1 (1,2EN), 2 (1A) and 7 (2A)
Motor2  CON 2           ' Motor 2 control on stamp pins 2, 4 and 6
                        ' SN754410 pins 9 (3,4EN), 10 (3A) and 15 (4A)
}
'ported to SPIN:
CON
  Motor1 = 1
  Motor2 = 2

  LOW    = 0
  HIGH   = 1

{BS2_code:  
Loop:
  DEBUG CR, "s"
  MotorID = Motor1
  GOSUB MotorBrake
  MotorID = Motor2
  GOSUB MotorBrake
  PAUSE 1000

....
  DEBUG "R"
  MotorID = Motor1
  GOSUB MotorReverse
  MotorID = Motor2
  GOSUB MotorReverse
  PAUSE 1000

  GOTO Loop
}
'ported to SPIN

PUB Main
  DIRA[noparse][[/noparse] Motor1 + 0 ] := 1 'setup IO-Pins as outputs
  DIRA[noparse][[/noparse] Motor1 + 2 ] := 1
  DIRA[noparse][[/noparse] Motor1 + 4 ] := 1
  
  DIRA[noparse][[/noparse] Motor2 + 0 ] := 1
  DIRA[noparse][[/noparse] Motor2 + 2 ] := 1
  DIRA[noparse][[/noparse] Motor2 + 4 ] := 1
  
  repeat
    MotorBrake(Motor1)
    MotorBrake(Motor2)
    WaitCnt(ClkFreq + cnt) 'wait for one second
    
    MotorCoast(Motor1)
    MotorCoast(Motor2)
    WaitCnt(ClkFreq + cnt) 'wait for one second
    
    MotorForward(Motor1)
    MotorForward(Motor2)
    WaitCnt(ClkFreq + cnt) 'wait for one second
    
    MotorReverse(Motor1)
    MotorReverse(Motor2)
    WaitCnt(ClkFreq + cnt) 'wait for one second
    'the INDENTION defines what belongs to the repeat-loop
    'no "end of loop statement required even NOT defined in SPIN


{BS2-Code:    
MotorCoast:
  LOW  MotorID
  HIGH MotorID + 2
  HIGH MotorID + 4
  RETURN
}
'ported to SPIN
PUB MotorCoast(MotorID)
  OUTA[noparse][[/noparse] MotorID + 0 ] := LOW   
  OUTA[noparse][[/noparse] MotorID + 2 ] := HIGH   
  OUTA[noparse][[/noparse] MotorID + 4 ] := HIGH   




{BS2-Code:    
MotorBrake:
  HIGH MotorID
  LOW  MotorID + 2
  LOW  MotorID + 4
  RETURN
}
'ported to SPIN
PUB MotorBrake(MotorID)
  OUTA[noparse][[/noparse] MotorID + 0 ] := HIGH   
  OUTA[noparse][[/noparse] MotorID + 2 ] := LOW   
  OUTA[noparse][[/noparse] MotorID + 4 ] := LOW   




{BS2-Code:    
MotorForward:
  HIGH MotorID
  HIGH MotorID + 2
  LOW  MotorID + 4
  RETURN
}
'ported to SPIN
PUB MotorForward(MotorID)
  OUTA[noparse][[/noparse] MotorID + 0 ] := HIGH   
  OUTA[noparse][[/noparse] MotorID + 2 ] := HIGH   
  OUTA[noparse][[/noparse] MotorID + 4 ] := LOW   




{BS2-Code:    
MotorReverse:
  HIGH MotorID
  LOW  MotorID + 2
  HIGH MotorID + 4
  RETURN  
}
'ported to SPIN
PUB MotorReverse(MotorID) 
  OUTA[noparse][[/noparse] MotorID + 0 ] := HIGH   
  OUTA[noparse][[/noparse] MotorID + 2 ] := LOW   
  OUTA[noparse][[/noparse] MotorID + 4 ] := HIGH

best regards

Stefan

noobmuncher · 2009-12-26 06:49

Now I am not usre if my wiring is correct, I will list it below and if someone can take a look at it and at the hobby engineering link www.hobbyengineering.com/appHBridge1A.html and let me know what i am doing wrong i would appreciate it.
Pin (of the SN754410) :
1: Vdd
2:P27
3: Motor 1 A
4: Vss
5: Vss
6: Motor 1 B
7: P26
8: Negative terminal on the battery
9: Vdd
10: P25
11:Motor 2 A
12: Vss
13: Vss
14:Motor 2 B
15: P24
16:Positive terminal on the battery

and the code (among many, that i have now tested) is

PUB LedsOn
repeat
dira[noparse][[/noparse]24..27] := %1111
outa[noparse][[/noparse]24..27] := %0101
waitcnt(clkfreq + cnt)
outa[noparse][[/noparse]24..27] := %1010
waitcnt(clkfreq + cnt)

Thank you so much, Happy Holidays!

noobmuncher · 2009-12-26 06:57

Wow thanks alot stefan! I will give it a try, I think the problem was I didn't have the EN set to anything, it was just going to Vdd. Where in your code can I change the variables to use the pins 27-24 and 20 and 19 though? I see this here:

Stefan said...
Motor1 CON 1 ' Motor 1 control on stamp pins 1, 3 and 5
' SN754410 pins 1 (1,2EN), 2 (1A) and 7 (2A)
Motor2 CON 2 ' Motor 2 control on stamp pins 2, 4 and 6
' SN754410 pins 9 (3,4EN), 10 (3A) and 15 (4A)

but I am sorry I am not sure where this is defined in the program.

Thanks again

noobmuncher · 2009-12-26 07:01

Never mind I think I figured it out now, slick programing by the way.

noobmuncher · 2009-12-26 07:13

So i rewired it to work with your code, however the program didn't seem to do anything. Any idea whats wrong?

StefanL38 · 2009-12-26 12:03

Hi,

Clock Loop mentioned that the SN754410-chip needs a SUPPLY-voltage of minimum 4.5V
so supplying it with 3.3V is too low

The IO-Pins start with zero not with 1

To do more analysing you have to provide a schematic of how you wired EVERYTHING
This means connections from Prop to SN754410 and SN754410 with the motor
With ALL pins numbered and named.

best regards

Stefan

noobmuncher · 2009-12-26 20:05

Okay thank you, will do as soon as I get a chance.

Just want to make sure this code doesn't fry my board before i try it

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