Mecanique's internal bootloader OSC

[SUNFLOWER]

MC Studio bootloader works great with xtal. But, there is always a but, when I load 18F4620_04.hex using meProg U2 with INTRC(INTIO2) configured then MC bootloader no longer functions, because (I think) there is no way (with my skill set) to set the bootloader speed at 1 MHz or set the target at 4 MHz with OSCCON.

This important because we want to simplify hardware in the field at scale and not use external crystals, allow code upgrades, and watch/modify data flow using a notebook serial port. It must be dirt cheap. The solar tracking code will be open source for places like India and China, posted in user-friendly BASIC. They hopefully will only need PBP + MC Studio Plus for local integration.

I saw in the forum a patch for 16F****. Is there something for 18F4620 using internal oscillators, perhaps working with PIC internal OSCCON default 1 MHz, or a method to smuggle in a 4 MHZ OSCCON ?

_OSC_INTIO67_1H

[Charles Linquis]

If I understand what you are trying to do correctly:

You can program the bootloader with a default oscillator (say 4MHz) and then - in your code, set the running frequency to 1Mhz. So yes, you can use the 4MHz version of the bootloader and run at another speed.

[SUNFLOWER]

Thanks, Charles, I am trying to bootload a micro running on internal oscillator (no external crystal). The configuration fuses were set correctly when the bootloader was installed but the micro defaults to 1 MHz during programming because the OSCCON register is cleared during programming. How can anyone work around this and load a micro without an external crystal?

[ScaleRobotics]

Hey Sunflower,

Since Mecanique's bootloader code is in hex form, I don't see a way to insert an osccon command, but maybe I am missing something.

Since it doesn't seem important which bootloader they use, in this case, I would use Tiny Bootloader: http://www.etc.ugal.ro/cchiculita/so...bootloader.htm . You can add the changes you need into the assembly source, then compile.

If I understand your project, you currently have it running on a Basic Stamp, but you need to do it cheaper, so you are turning to PBP. You say you wanted each location to have a copy of PBP and MCSP. But did not want to put a crystal on it, because it cost too much. Something doesn't add up?

Basic Stamp II $49.00
PBP + MCSP + PIC18F4620 = $304.90

Difference = loads of crystals

[SUNFLOWER]

Thanks. Perhaps we could plant code in space reserved but not used in bootloader space that would drive the micro at 4MHz internal before programming. (I could not do that, never assembled anything.)

Cheaper to fix the software than to buy crystals.

Cheaper by the thousands. Basic Stamp is a great R&D platform. $5 PIC (plus lower power and more peripherals) would stomp Stamp prices in production.

[ScaleRobotics]

Cheaper by the thousands. Basic Stamp is a great R&D platform. $5 PIC (plus lower power and more peripherals) would stomp Stamp prices in production.

It is not clear that you have added the cost of PBP and MCSP in the equation?

The solar tracking code will be open source for places like India and China, posted in user-friendly BASIC. They hopefully will only need PBP + MC Studio Plus for local integration.

[SUNFLOWER]

I know this concerns meLabs. Once compiled mass production begins. So meLabs only get paid per software development workstation, not per dish. That is the future. For now, multiple startups will require PBP for developing their proprietary Dish_Operating_System.hex. Our kernel DOS is open source as a starting point. We have bigger fish to fry.

[SUNFLOWER]

MicroChip Bootloader P1618QP.EXE and Tiny_Loader both have the same conflict with internal oscillators and bootloaders.

Anyway, I think I need help to jump past bootload space, set one bit OSCCON.5 = 1, then jump to the start of bootload and program at 4 MHz. I would be forever grateful.

[ScaleRobotics]

Hmmm,

Did you have

define loader_used 1

At the top of your program? This tells PBP to skip the first four locations (I think), which are necessary for the bootloader.

[SUNFLOWER]

Yes did that, and it did work once, tantalizingly close to crystal freedom.

[Charles Linquis]

We have some boards that are too small for an additional MAX232 chip. We bring out the Tx and Rx pins anyway (along with Vcc and GND). When programming is needed, we plug in a board that has a MAX232 chip and a DB9 connector on it.

So we can have a bootloader AND a small, low-cost board.

The real upside is that having a serial port is one of the best debugging tools around.

The boards start up at 4Mhz, but the code "downshifts" to 1Mhz for power savings. It is a tiny temperature sensor, and any dissipation shows up as a temperature error. The chips are 18F2321s and run on the internal oscillator only.

[SUNFLOWER]

Yes Bruce I was going down that road eliminating the MAX232 until I considered the advantages of loader-free possibilities with boots. Firmware updates will be all over the map, some in the most remote areas of India. And they are religious about not spending money. So I thought eliminating loaders, like U2, would be a good trade-off for using the MAX232 (and I really like hardware serial functions HSEROUT/HSERIN). I did read Mecanique worries about internal oscillation drift, so maybe if we want to eliminate programming hardware we should just work with crystals, totally not needed for tracking a slow moving sun. Will defer until the industry matures and PICs operating crystal-free can be reliably bootloaded. It is amazing how much stuff is unexpected.

It would be great if PICs also had internal voltage regulators and internal MAX232. Maybe someday.

Thanks,
Doug

[SUNFLOWER]

Good ideas, Charles, I will consider that type of connection. So you bootload with internal oscillation, what ambient temperatures, and do you experience bootloader reliability issues?

Being user-friendly is very important. I agree that the serial port is useful. Olimex makes a PIC carrier board with the all the needed peripherals for (I hope) less than $10 at scale.

[Charles Linquis]

We have chamber-tested random units at -40C and 100C, about 30 units total.

Never any failures.

I assure you, you won't have any trouble at any temperatures humans would want to be at for any length of time.

About 90% of what we do is military. Reliability is important to them, too.

[ScaleRobotics]

Yeah, I think you are right, somehow its stepping on its tail. If you would like, you could read the chip after it steps on its tail, and send me the hex. I'll try to see what's going on with it.

[SUNFLOWER]

Do not have time to manage attachments, got a dinner date, but the before and after look the same... and now Tiny does not find target after successfully loading test program. [before and after hex files]

0000- ef00 f07f ffff ffff ffff ffff ffff ffff


ff30- ffff ffff ffff ffff 0000 0000 0000 0000
ff40- 0e24 6eac 0e19 6eaf 0e90 6eab 0e60 6ed3
ff50- d846 08c1 e153 0e4f 6ead 0e4b 6ead 6a00
ff60- d83e 6ef8 6e07 d83b 6ef7 6ea9 d838 6ef6
ff70- 6ea8 d835 6e01 2a01 ee00 f009 6ef5 d82f
ff80- 6eec 2e01 d7fb 6600 d01f ac07 d003 0e04
ff90- d81e d018 ae07 d004 000c 0ec4 d818 d012
ffa0- 0e94 d815 000a 0e08 6e05 ee00 f00a 0e08
ffb0- 6e06 50ee 6ef5 000f 2e06 d7fb 0e84 d807
ffc0- 2e05 d7f5 94a6 d7c9 0e4e 6ead d7c8 6ea6
ffd0- 0e55 6ea7 0eaa 6ea7 82a6 0000 0012 0e03
ffe0- 6e02 6a03 6a04 aa9e d003 50ae 2600 0012
fff0- 2e04 d7f9 2e03 d7f6 2e02 d7f3 9eab d79c


0000- ef00 f07f ffff ffff 0f40 6e01 0b7f bc01


ff30- ffff ffff ffff ffff efb8 f001 ffff ffff
ff40- 0e24 6eac 0e19 6eaf 0e90 6eab 0e60 6ed3
ff50- d846 08c1 e153 0e4f 6ead 0e4b 6ead 6a00
ff60- d83e 6ef8 6e07 d83b 6ef7 6ea9 d838 6ef6
ff70- 6ea8 d835 6e01 2a01 ee00 f009 6ef5 d82f
ff80- 6eec 2e01 d7fb 6600 d01f ac07 d003 0e04
ff90- d81e d018 ae07 d004 000c 0ec4 d818 d012
ffa0- 0e94 d815 000a 0e08 6e05 ee00 f00a 0e08
ffb0- 6e06 50ee 6ef5 000f 2e06 d7fb 0e84 d807
ffc0- 2e05 d7f5 94a6 d7c9 0e4e 6ead d7c8 6ea6
ffd0- 0e55 6ea7 0eaa 6ea7 82a6 0000 0012 0e03
ffe0- 6e02 6a03 6a04 aa9e d003 50ae 2600 0012
fff0- 2e04 d7f9 2e03 d7f6 2e02 d7f3 9eab d79c

[SUNFLOWER]

Yup, line ff30 did change. Maybe it is Tiny PIC reset after programming. The PIC does reset after programming.

[ScaleRobotics]

I had a PIC18F4620 laying around, so I tried the code here. The Tiny Bootloader with internal osc seems to work fine here. I don't get an overwrite of my FF30 line though. Is your code very large, or is it writing to locations of the code space?

Also, this may be dumb, but Tiny bootloader will automatically see your chip the first time, without you having to reset the device. After you have used it to load your chip with your code the first time, you will have to reset power within one second of pressing the write button.

[SUNFLOWER]

Scalerobotics, I am eternally grateful.

I spent the last few hours compiling many changes to tinybld 18F4620.asm (configuration fuses, boot space, hex files, etc.). The new bytes in FF30 were just the first words of my program relocated to make space for the boot call.

I Just now discovered what you wrote above... reset not initially needed but then it is after the first program loaded. Your Tiny hack is working perfectly.

It is good to have open source boots for hungry people.

THANK YOU!

Doug

[ScaleRobotics]

Not a problem Doug, glad it worked for you. By the way I love your project. http://www.harbornet.com/sunflower/pvdish.html

Charles and Bert have convinced me as well. So my next project will run on internal oscillator.

And for those really cheap, small projects, you can get away without a max232 chip with another modification to the source code. http://www.picbasic.co.uk/forum/show...2538#post82538

Walter

Edit: Here I am with my solar install:

[cncmachineguy]

Charles and Bert have convinced me as well. So my next project will run on internal oscillator.

Nice to know I can convince someone of something

welcome to the "inside"

[SUNFLOWER]

California solar, kudos scalerobotics. The solar dish is a dangerous autonomous robot. It must know where the sun is from a clock time/date algorithm and where the dish points. Otherwise, if the sun suddenly appears from behind a cloud then a rebel dish could melt rocks or start fires. I was once set on fire by walking into the invisible beam. It was like being hit with a 10 kW laser.

It appears the dish control system will cost $15, plus sensors $? and Pololu dual motor Hbridge TB6612FNG $8 for one.

The MAX232 is not so dear. Olimex make a populated PIC 40 carrier board ~ 1 @ $17, or 150 @ $13, or thousands w/o crystals @ <$10. Includes PIC 40 socket, MAX232, DB-9 plug, LM317 +3.3V / +5V power, status led, push button, 20 MHz crystal, reset button, ICSP, and circuit area for things like a DS1307 clock. Looks good for production start up with easy scale up.

http://www.olimex.com/dev/pic-p40.html

The business model is mass production from existing mass produced materials and parts all installed/maintained globally via local integration without central command and control. Local return on investment must be 20% (without subsidies) compared to current natural gas prices.

The huge and urgent objective is international global warming mitigation.

Best,
Doug

[Bruce]

Charles,

We have chamber-tested random units at -40C and 100C, about 30 units total.

Were you testing this by boot-loading with the internal osc and a serial loader, or just testing to see if the PIC failed at these temps?

If so - which PIC were you using? I've had problems in Colorado when the temperature fell below freezing with serial loaders using the internal osc. And more when the board was in an enclosure exposed to direct sun.

Just curious. That's pretty good if you were boot-loading with a serial loader using the internal osc at these temperatures.

[Charles Linquis]

Charles,


Were you testing this by boot-loading with the internal osc and a serial loader, or just testing to see if the PIC failed at these temps?

If so - which PIC were you using? I've had problems in Colorado when the temperature fell below freezing with serial loaders using the internal osc. And more when the board was in an enclosure exposed to direct sun.

Just curious. That's pretty good if you were boot-loading with a serial loader using the internal osc at these temperatures.

We were not actually boot-loading at those temps. We were, however, continuously doing serial I/O at 19,200 baud. No problems. Note that we were using 18LF2321's at 5V.
Many years ago, I found that some other chips (in the 16F series) were not nearly so accurate - or stable.

[ScaleRobotics]

Otherwise, if the sun suddenly appears from behind a cloud then a rebel dish could melt rocks

Melting Rocks = Cool!!

The huge and urgent objective is international global warming mitigation.

Very Cool!!

I was once set on fire by walking into the invisible beam. It was like being hit with a 10 kW laser.

Most uncool!

Very nice project indeed. (And don't forget to wear your sun block!)

[SUNFLOWER]

Solar melted rocks made great visitor gifts.

We flashed hot dogs on sticks into carbon but could not get a marshmallow hot. The rules at Federal solar concentrator sites include, "Always wear white clothes and white caps".