PICAXE-08M Zapped?

By kankatee
2008-12-04 02:40

I have a PICAXE-08M that I belive is zapped. Not sure how I would have killed it but the program editor will no longer download code to it. When I check the firmware, it see's that it is an 08M, etc. 1) Can I confirm the death of this chip for sure? 2) Is it possible to ressurect the chip?

Worth mentioning, we can eliminate the USB, program, or circuit being the point of failure since my 14M works just fine.

Thanks in advance.

By OddBot @ Thu, 2008-12-04 04:30

I've accidently connected

I've accidently connected power to a 14M around the wrong way and despite getting very warm it worked fine once I connected power the right way so these chips are pretty tough.

Did you change the internal clock frequency to 8MHz either in the options or in the last program you loaded into the chip? I've had problems before where the program editor was set wrong for my IC. Otherwise start the download with no power to the 08M and then connect the power before the program editor times out.

This is a hard reset and will ensure that the 08M is at 4MHz.

By voodoobot @ Thu, 2008-12-04 04:40

have you checked the

have you checked the battery, that could prevent it from getting proged

By kankatee @ Thu, 2008-12-04 14:16

Setfreq m8

When I had the 08M working I did have it overclocked to 8mhz. Although the prog editor reads 4mhz, no go.

Update. After fidgeting with a hard reset, everything seems to be back to normal. It didn't work the first time I tried a hard reset, I had to do it a few times before the editor recognized and downloaded to the chip.

All good. Thanks for the help!

By jklug80 @ Thu, 2008-12-04 19:01

This happens to be

This happens to be frequently when I use breadboards or my own circuits. I have to hit F5 and then connect the batter or flip the switch to provide power. I don't use my picaxe project boards much so I'm not sure if it is a problem with picaxe or my circuit. Turning it on after pressing f5 usually works after a few tries.

By kankatee @ Thu, 2008-12-04 14:17

PICAXE with regulated power

Do you all run your PICAXE chips from AA batteries or do you all use a regulated power supply? I have tried using a 9vdc/400ma power supply with a 5vdc regulator, but I seem to get variable and inconsistent results.

Thoughts?

By voodoobot @ Thu, 2008-12-04 18:47

I've used 4 AAA cells (6v)

I've used 4 AAA cells (6v) unreged without issue on a couple of my paxes without issue so far. I've also run with a (7805)regulated 9v(energizer I think) cell without issue.

~~One thing I noted when looking at the image is that your serin isn't tied to a common ground. It's advisable to do so, as this can potentially cause inconsistant operation issues.~~

scratch that, didn't see the ground line at first...dang where are my glasses!

By kankatee @ Thu, 2008-12-04 19:10

Yes, 7805s are good

But have you used one in conjunction with a power adapter?

By jklug80 @ Thu, 2008-12-04 19:19

There was another thread

There was another thread when someone tried to run a picaxe using a wall adapter. The problem was it supplied too much voltage when there wasn't a load on it. I believe it fried something, but it wasn't a picaxe. It was a servo board or motor driver that was rated for 12volts, but without a load the adapter send 14 or 16.

Edit: Found the link http://letsmakerobots.com/node/2040

By voodoobot @ Fri, 2008-12-05 19:11

negative. I only use sources

negative. I only use sources that I plan to use in a project which are mostly rechargable batteries. I do(okay it's really my dads) have a bench supply I think it's regulated to 5 volts or 9 volts, but I never tried it.

By kankatee @ Fri, 2008-12-05 19:43

Makes sense really

Why not prototype with the real thing? If it's going to use a 7.2 nimh, test with a 7.2 nimh.

By voodoobot @ Fri, 2008-12-05 21:58

Thats what I was saying. I

Thats what I was saying. I mainly use 9.6v nimh rechargable cells or 9v(6xAA/AAA). Those are what I refer to as my sources.

By kankatee @ Fri, 2008-12-05 22:33

Haha

I know. My above comment was supposed to imply that it makes perfect sense. As in, why do anything else?

By OddBot @ Fri, 2008-12-05 12:56

Power supply

I make my own boards that can run from 6V-15V or more. I use a low dropout voltage regulator for less than 8V otherwise a 7805 is fine. It is important to have decoupling / filtering capacitors in your power supply to allow for spikes and noisy loads. Use a 0.1uF polyester or monolithic (ceramic) and at least 100uF electrolytics on both the regulator inputs and outputs. Since a 9V can accidently touch the contacts wrong way round during connection it's a good idea to have a diode in series to protect against reverse polarity. I'd draw you a schematic but my software is locking up since my last so called "security update" :(

By kankatee @ Fri, 2008-12-05 14:11

Ah, the security update

Good info. Keep me posted on a schematic. By the way, what do you use to draw your schedmatics? Any special software? Thanks.

By OddBot @ Fri, 2008-12-05 23:28

Power regulator schematic

Ok, got Corel draw working again. It isn't a program designed for schematics but once you've drawn the components and set up the page right the parts just click together. Here's the schematic.

This is a general purpose regulator that will work with a plugpack or batteries. I've shown 470uF capacitors which should be fine for a 9V battery and MCU operating LEDs.

If you are running servos or other small motors on the 5V output then increase both 470uF to at least 2200uF and add an extra 0.1uF for every motor as close as possible to the motor.

By kankatee @ Sun, 2008-12-07 14:12

Thanks

OddBot- Thanks for the schematic. This helps.

Gotta love Corel Draw..

By CaptainTuna @ Thu, 2008-12-04 17:04

do you mean the progress bar

do you mean the progress bar stops in between and you'll have to start download again? That also happened to me. Anyway... are you using codes such as SERIN that wait for a command to be received or, mroe in general, wait for something to happen before going on?

By kankatee @ Thu, 2008-12-04 17:32

Nah

No, the progress bar never want partially across. Just never started. Not sure if the code previously downloaded on the 08 contained SERIN or SEROUT. The new code I was trying to download (and ultimately worked) was as basic as it gets. None the less, it's all solved.