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Forum Index : Microcontroller and PC projects : Beta Testers Wanted
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| JohnS Guru  Joined: 18/11/2011 Location: United KingdomPosts: 3819 |
I don't understand you. It's quite rare to hunt here. I've no desire at all to use MPIDE or its compiler which I understand by default is somewhat crippled. I can see what I would lose but can see no gains. I use gcc with optimisations, mostly for ARM (and x86 etc). The last thing I want is a crippled version that's in a new IDE and hasn't even got optimisations. No way! I cannot but shrink in horror and disgust at Microchip's stupid behaviour on this. John |
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CircuitGizmos Guru Joined: 08/09/2011 Location: United StatesPosts: 1425 |
Buy a pre-programmed micromite chip from CG. Micromites and Maximites! - Beginning Maximite |
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elproducts Senior Member  Joined: 19/06/2011 Location: United StatesPosts: 282 |
I don't see it on your website. Am I missing it? www.elproducts.com |
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| CircuitGizmos Guru Joined: 08/09/2011 Location: United StatesPosts: 1425 |
Not there yet. Can't put it there until it is out of Beta. Micromites and Maximites! - Beginning Maximite |
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Geoffg Guru Joined: 06/06/2011 Location: AustraliaPosts: 3199 |
On the subject of the 47uF cap required for the Micromite (Pic32 Vcap). You can use a 10uF and in fact that is Microchip's recommended value. Also, for the PIC32MX150/250 the capacitor only needs an ESR of 1 ohm or less (which is a fairly relaxed specification). Aa a result, I was going to recommend a 10 uF but then I tested a batch of cheap tantalum caps that I received from China and a number of them were over 1 ohm. So I figured that it would be safer to recommend a 47 uF tantalum as capacitors of that value would almost certainly have an ESR under 1 ohm (generally with increasing capacitance the ESR drops). Geoff Geoff Graham - http://geoffg.net |
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| plasma Guru Joined: 08/04/2012 Location: GermanyPosts: 437 |
Hi, finally good News . I've got my first Micromite running. burning with Mplab ipe and a pickit 3 works fine . Tera Term also . if you use Mplad Ipe and u will use the power from pickit 3 so u need the advanced Mode for. here can u set up the Power for the chip from the Pickit 3. I use a Tantalum for the c , in my case a 47/ 32 v and it works ok. For the Usb/TTL i use USB/TTL Ebay link It have also a 3,3 V output with 50 milliamps , this powered my Testdevice. Maybe this is usefull for other Micromite Fans . Thx Geoff for your hard Work ! U make it easy for us to create some cool Parts ! Gtx |
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Grogster Admin Group  Joined: 31/12/2012 Location: New ZealandPosts: 9310 |
I can also chime in here and report that I was able to program the HEX into the blank PIC32 last night, but I have not yet had a chance to hook it up to a terminal, mainly as at this time, I only have 5v TTL logic-converters, no CMOS 3v3 ones, so I am going to have to build one - anyone got any suggestions in that regard? I do have some of those prolific USB-Serial converters, but I have not checked them for the serial voltage - I suspect they will be at least 5v, probably closer to the true RS232, which would instantly kill the PIC32 chip. What are others using on their micromites? Smoke makes things work. When the smoke gets out, it stops! |
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vasi Guru Joined: 23/03/2007 Location: RomaniaPosts: 1697 |
This one? Hobbit name: Togo Toadfoot of Frogmorton Elvish name: Mablung Miriel Beyound Arduino Lang |
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| Alan68 Newbie  Joined: 28/01/2013 Location: AustraliaPosts: 17 |
Hi, I've had my PIC32MX150 working for a few day's if you look at the photo, you can see I'm using a 47uF 16V electrolytic. I'm powering the whole circuit from a USB to serial TTL interface that has a 3.3V and 5v output, the USB interface is plugged into a powered USB hub that keeps the whole lot running 24 hours a day. 
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| Grogster Admin Group Joined: 31/12/2012 Location: New ZealandPosts: 9310 |
@ vasi - thanks. That sounds like the ticket. Great. Something else to order.   Smoke makes things work. When the smoke gets out, it stops! |
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| JohnS Guru Joined: 18/11/2011 Location: United KingdomPosts: 3819 |
Grogster - The Prolific USB ones I have are 3.3V or 5V, you can select. But actually you don't need to as just Tx Rx & Gnd is what I find works (think about it). John |
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| Grogster Admin Group Joined: 31/12/2012 Location: New ZealandPosts: 9310 |
Yes, but TXD and RXD on the 232 output(with respect to deck/GND), will still be at a higher +/- voltage then allowed by the PIC32's 3v3 tolerance, so I am not sure you can get away with that, and the datasheet for the MM specifically says in bold NOT to connect true RS232 - basically, you will cook the chip is what the PDF is saying. I have found a couple of MAX3232's here, so I can probably swap the chip in one of the many MAX202 TTL-232 converters I already have, to get the 3v3 CMOS logic level I need. I'm itching to play with the MM - don't want to wait for something else to arrive in the post.  Smoke makes things work. When the smoke gets out, it stops! |
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| Alan68 Newbie Joined: 28/01/2013 Location: AustraliaPosts: 17 |
Hi, I've measured the voltage on pin 12 (console data in) and it's 4.6V from the USB to TTL interface, the Microchip manual say's that pin 12 is not a 5V tolerant pin. I've used 2 resistors to make a potential divider, 3.9K from the TTL output of the USB to serial to pin 12 and a 10K from pin 12 to 0V. |
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| Geoffg Guru Joined: 06/06/2011 Location: AustraliaPosts: 3199 |
Using a converter with a 5V output should not be a problem. All you need is a resistor (say 4.7K) in series with the Tx from the converter to the Rx on the Micromite. The internal protection diodes in the PIC32 will clip the input voltage to 3.3V and the resistor will limit the current through said diodes. You can directly connect the signal going the other way (from the Micromite Tx to the converter's Rx) as most converters will have their hi/lo threshold at about 1.5V. Geoff Geoff Graham - http://geoffg.net |
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TassyJim Guru Joined: 07/08/2011 Location: AustraliaPosts: 6103 |
You could put a 10k resistor in series with the Rx line (Pin 12) to protect the uMite from any overvoltage. It's a good idea anyway. For full 12V Geoff suggests using a 47k resistor. Jim Geoff beat me to it! VK7JH MMedit  MMBasic Help |
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| Grogster Admin Group Joined: 31/12/2012 Location: New ZealandPosts: 9310 |
Great info - thanks, guys.  Smoke makes things work. When the smoke gets out, it stops! |
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| TassyJim Guru Joined: 07/08/2011 Location: AustraliaPosts: 6103 |
More playing with the TTL voltages. The converter I am using has 3.5V on the 3.3V rail so I tried my suggestion and put a 4.7k resistor in series with pin 12. No go, too much voltage drop. The input was only getting pulled down to about 1 volt. I reduced the series resistor to 1k and all is functioning again. The other USB to TTL convertor has a much better 3.3V output. Both converters have 3.3V and 5V available. Jim VK7JH MMedit  MMBasic Help |
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| Grogster Admin Group Joined: 31/12/2012 Location: New ZealandPosts: 9310 |
I have just found one of my homebake converters I made when I was playing with a lot of PICAXE chips and XBEE's. This board can do 5v TTL or 3v3 CMOS to RS232, by just moving a jumper on the PCB. It also has regulated 5v and 3v3 outputs to power the device you are talking to. This board uses 7805 and 3940 regulators, and a MAX3232, which can operate at either 3v3 or 5v depending on what you need - you just feed the chip with the voltage that you need to talk to the thing on 5v or 3v3. RIGHT - now I think I can actually get things hooked up and start tinkering.  Smoke makes things work. When the smoke gets out, it stops! |
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| viscomjim Guru Joined: 08/01/2014 Location: United StatesPosts: 925 |
Hi All, Just got blinky led with uMite! I used the pickit3 IPE (first time), loaded hex code, programmed chip using pickit 3 power (used advanced setting with "microchip" code), connected usb to serial board (this one... http://www.adafruit.com/products/284) just gnd, tx, rx, already set to 3.3v. Don't use power pin as it is set to 5vdc. Board can easily be reconfigured to 3.3v by cutting jumper on back and soldering 3.3v jumper, then vcc can come from adafruit board. Set up com port settings in device manager and tera term. Wrote little program. LED blinks. Life is good!!! Thanks Geoff, now on to fun stuff!!!
Jim |
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MicroBlocks Guru Joined: 12/05/2012 Location: ThailandPosts: 2209 |
I have great result using two diodes in series with the USB supply. When measured the USB often is about 4.5-4.6v. Substract about 0.6v per diode and two diodes in series will give you a neat 3.3v. When you want to do this make sure you measure the voltages first. Some diodes have a lower voltage drop and some USB give 5v, requiring one diode more. Also put a load on it otherwise you get an incorrect reading. It does not beat a regulator, but to get a 3.3v quickly it works well. It also works well with 3 AA batteries as a power source. Microblocks. Build with logic. |
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