Battery Problem

Zenexer · 2011-09-03 15:37

I am trying to power a Propeller with four AAA batteries in series. 3.3 voltage regulator from the Parallax Store. 0.1 uF capacitor on the unregulated voltage, 10 uF capacitor on the regulated voltage. No matter how simple I make my circuit, the program will not run unless I limit it to a single cog. The moment I start a second cog, the propeller dies, as if I pulled the plug. I've tried fiddling with the capacitors, disabling the built-in brownout detector, and removing EEPROM. The only solution seems to be AC power: I just can't get it to run off these (tested good, brand new) batteries.

Zenexer · 2011-09-03 15:58

Slight adjustment to my previous post. It appears to be more related to the number of objects that I have rather than the number of cogs. I can start a second cog if I have three objects (the main object and two sub-objects), but any more than that and it dies when I start the second cog, even with the exact same code--minus the object difference.

Duane Degn · 2011-09-03 15:59

This does seem strange.

When you say "tested good" how did you test them? Dead batteries will still read almost normal voltage levels without a load.

Duane

Zenexer · 2011-09-03 16:05

Some cheap RadioShack battery tester. They came straight from the package, too.

If it helps, I tried putting an LED across Vss and Vdd (with a proper resistor). It never dims or goes out noticeably.

To eliminate bad components, I tried with a second breadboard and a new set of (fresh) components, all from Parallax. Same effect.

I tried with four brand new AA batteries. Same effect.

Zenexer · 2011-09-03 16:11

Here's my WORKING code. If I get any more complex than this, the Propeller dies around Console.Init.

#define TERMINAL

CON
  _CLKMODE = XTAL1 + PLL16X
  _XINFREQ = 5_000_000

OBJ
  Console: "Console"
  Card: "Card"

PUB Main
  dira[0]~~
  outa[0]~~
  waitcnt(CLKFREQ * 2 + cnt)
  Console.Init
  Console.ClearScreen
  Console.WriteLine(string("Test"))

Duane Degn · 2011-09-03 16:13

How about some non-working code?

Zenexer · 2011-09-03 16:19

Non-working code. Dies somewhere in/before/after Console.Init.

#define TERMINAL

CON
  _CLKMODE = XTAL1 + PLL16X
  _XINFREQ = 5_000_000

  #1
  DOPinR
  CLKPinR
  DIPinR
  CSPinR[2]
  CDPinR

  #9
  DOPinW
  CLKPinW
  DIPinW
  CSPinW[2]
  CDPinW

OBJ
  FatR: "SD-MMC_FATEngine"
  FatW: "SD-MMC_FATEngine"
  Console: "Console"

PUB Main | r
  dira[0]~~
  outa[0]~~

 Console.Init

  Console.WriteLine(string("Starting FAT read engine."))
  ifnot \FatR.FATEngineStart(DOPinR, CLKPinR, DIPinR, CSPinR, -1, CDPinR, -1, -1, -1)
    Console.WriteLine(string("Could not start FAT read engine."))
    return

  Console.WriteLine(string("Starting FAT write engine."))
  ifnot \FatW.FATEngineStart(DOPinW, CLKPinW, DIPinW, CSPinW, -1, CDPinW, -1, -1, -1)
    Console.WriteLine(string("Could not start FAT write engine."))
    return

  Console.WriteLine(string("Mounting read file system."))
  r := FatR.MountPartition(0)
  ifnot (r == true) OR (r == false)
    Console.WriteString(string("Error mounting read file system: "))
    Console.WriteLine(r)
    return

  Console.WriteLine(string("Formatting and mounting write file system."))
  r := FatR.FormatPartition(0)
  ifnot (r == true) OR (r == false)
    Console.WriteString(string("Error formatting/mounting write file system: "))
    Console.WriteLine(r)
    return

  Console.WriteLine(string("Stopping FAT engines."))
  \FatR.UnmountPartition
  \FatW.UnmountPartition
  \FatR.FATEngineStop
  \FatW.FATEngineStop
  Console.WriteLine(string("Done."))

Zenexer · 2011-09-03 16:21

I keep thinking there must be an abort call somewhere, but then I remind myself that it works on AC power.

Zenexer · 2011-09-03 16:22

This code works, though Console.Init appears to abort, since Run stops running around there. I think I need to reassess the problem.

#define TERMINAL

CON
  _CLKMODE = XTAL1 + PLL16X
  _XINFREQ = 5_000_000

  #1
  DOPinR
  CLKPinR
  DIPinR
  CSPinR[2]
  CDPinR

  #9
  DOPinW
  CLKPinW
  DIPinW
  CSPinW[2]
  CDPinW

OBJ
  FatR: "SD-MMC_FATEngine"
  FatW: "SD-MMC_FATEngine"
  Console: "Console"

PUB Main
  dira[0]~~
  outa[0]~~
  \Run
  repeat
    outa[0] := !outa[0]
    waitcnt(CLKFREQ / 10 + cnt)

PRI Run | r
 Console.Init

  Console.WriteLine(string("Starting FAT read engine."))
  ifnot \FatR.FATEngineStart(DOPinR, CLKPinR, DIPinR, CSPinR, -1, CDPinR, -1, -1, -1)
    Console.WriteLine(string("Could not start FAT read engine."))
    return

  Console.WriteLine(string("Starting FAT write engine."))
  ifnot \FatW.FATEngineStart(DOPinW, CLKPinW, DIPinW, CSPinW, -1, CDPinW, -1, -1, -1)
    Console.WriteLine(string("Could not start FAT write engine."))
    return

  Console.WriteLine(string("Mounting read file system."))
  r := FatR.MountPartition(0)
  ifnot (r == true) OR (r == false)
    Console.WriteString(string("Error mounting read file system: "))
    Console.WriteLine(r)
    return

  Console.WriteLine(string("Formatting and mounting write file system."))
  r := FatR.FormatPartition(0)
  ifnot (r == true) OR (r == false)
    Console.WriteString(string("Error formatting/mounting write file system: "))
    Console.WriteLine(r)
    return

  Console.WriteLine(string("Stopping FAT engines."))
  \FatR.UnmountPartition
  \FatW.UnmountPartition
  \FatR.FATEngineStop
  \FatW.FATEngineStop
  Console.WriteLine(string("Done."))

Zenexer · 2011-09-03 16:29

That's really strange... suddenly everything is working. I'm going to play around with it a bit to make sure it's really solved.

Zenexer · 2011-09-03 16:39

I'm not going to mark this as solved or unsolved, since I have absolutely no clue what happened. It just started working with the exact same code and circuit.

kwinn · 2011-09-03 17:34

Sounds like a bad contact or cold/no solder joint that you have temporarily fixed by handling the hardware.

Phil Pilgrim (PhiPi) · 2011-09-03 17:47

How many 0.1uF ceramic bypass caps do you have between Vdd and Vss right at the power pins on the Propeller chip? (If the answer is "none", this could be the root of your problems.) A 10uF filter capacitor is not enough. You also need local bypassing.

-Phil

bsnut · 2011-09-03 23:48

I agree with Phil on this one and suggest you to look at a schmatic for one of the Parallax boards to give you an idea how they setup there cap values for providing power to the Propeller

Mark_T · 2011-09-05 03:57

kwinn wrote: »

Sounds like a bad contact or cold/no solder joint that you have temporarily fixed by handling the hardware.

I'd agree with this diagnosis - I've been hit in the past by some cheap battery holders that have dodgy riveted contacts (leading to sporadic intermittent behaviour), this would explain the behaviour nicely.

Battery Problem

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