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  1. #61
    Senior Membrane spirilis's Avatar
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    Nice! Very cool, never really studied PSU design much.
    So JP1 basically takes the rectified output of a AC transformer? (the big blue thing)
    intp | type 9w1 sp/sx/so

  2. #62
    resonance entropie's Avatar
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    Yes or you can use a normal DC wall wart @ a maximum of 23 Volts. I used the AC trafo tho cause then you can solder a cable to it and plug it into the wall permanently. If you'ld use a normal DC wall wart efficiency would prolly go down too (most of those things get pretty hot in my experience).

    Thats the cable european standard soldered onto the trafo:


    Here's the layout and partlist. If you have trouble with the german let me know.

    [URL]https://www.youtube.com/watch?v=tEBvftJUwDw&t=0s[/URL]

  3. #63
    Senior Membrane spirilis's Avatar
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    Looked at the datasheet for that TS19377 chip. Will file that in the back of my mind if I ever decide to go nuts with high-power white LEDs one of these days
    intp | type 9w1 sp/sx/so

  4. #64
    Senior Membrane spirilis's Avatar
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    I do enjoy the look of a good home-etched PCB now and then.

    (special BoosterPack to provide an FTDI FT232RL based bootloader and/or UART for my Renesas YRPBRX210 promo board... should let me bypass the SEGGER J-Link onboard to reflash the chip using fully open-source tools instead)
    intp | type 9w1 sp/sx/so

  5. #65
    resonance entropie's Avatar
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    Quote Originally Posted by spirilis View Post
    I do enjoy the look of a good home-etched PCB now and then.

    (special BoosterPack to provide an FTDI FT232RL based bootloader and/or UART for my Renesas YRPBRX210 promo board... should let me bypass the SEGGER J-Link onboard to reflash the chip using fully open-source tools instead)
    Yes that looks great indeed. Do you have professional etching tools with temperature regulation and oxygen circulation ? I only etch in a petri disc and never get that good results .

    Btw I often have noticed in american designs that the ground layer is created with that circle pattern. Why do you do that exactly, to make it look more cool or has it an EMC effect ? Technically if you dont make the ground layer solid you'ld have to use more etching liquid, no ?!
    [URL]https://www.youtube.com/watch?v=tEBvftJUwDw&t=0s[/URL]

  6. #66
    Senior Membrane spirilis's Avatar
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    Quote Originally Posted by entropie View Post
    Yes that looks great indeed. Do you have professional etching tools with temperature regulation and oxygen circulation ? I only etch in a petri disc and never get that good results .

    Btw I often have noticed in american designs that the ground layer is created with that circle pattern. Why do you do that exactly, to make it look more cool or has it an EMC effect ? Technically if you dont make the ground layer solid you'ld have to use more etching liquid, no ?!
    No, I use a set of ziplock bags (board inside a small sandwich bag, that inside a heavy-duty 1qt bag, which is stuffed inside another 1qt bag, at the very end of the etching & cleaning I keep the acid inside the bags, seal them up & put them in a large 1gal heavy-duty bag and throw it in the trash). Also I add Citric Acid to my ferric chloride, helps it etch faster supposedly. Seems to work anyway. Then I sit it down on my workbench and fold the ziplock bag's zipper over and just massage it side to side, sloshing the chemicals around, picking up the whole bag and putting it against the light to see when I'm done.

    I think the key for precision is the laminator--I use a laminator to transfer the toner, not a clothes iron.
    The ground plane isn't anything fancy, just one of the patterns available in DipTrace (I don't use eagle). I learned most of my home-etching stuff and even my original technique & supplies from this guy -- http://www.pcbfx.com/

    He recommended using a crosshatched ground plane to avoid straining the laser printer, i.e. having it dump a lot of toner at once may cause it to deposit a thinner layer which could let a little acid through the etch-resist. In practice that doesn't seem to be the case, and I may just switch to solid ground planes for home work soon. My Samsung laser printer pretty much rocks. Also it's a pain in the ass to get the black toner off the board with the crosshatch pattern--toner likes to get stuck in those little holes. I usually have to pour acetone straight on the board and let it sit a few seconds before scrubbing, once or twice, to get it looking decent.
    I doubt the crosshatch has any bearing on EMC (if anything, it may worsen it for double-sided designs, although I don't do any double-sided stuff yet at home, I save that for the professional fabs )
    intp | type 9w1 sp/sx/so

  7. #67
    Senior Membrane spirilis's Avatar
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    Finally did drill & solder one of those boards, and it works... so now I have fully open-source tools (HW & SW) for flashing the Renesas RX210 chip on the YRPBRX210 promo board from my MacBook Pro. Got it working too, made some custom LD linker scripts to accommodate the RX210's unique differences from its bigger brother (newlib's default rx.ld is tailored for the RX600 series), got an LED blinking.

    Now I'm reading about FreeRTOS and bought one of their DRM-restricted PDF book sets (specifically for the Renesas RX600 series plus the reference guide) because I think it's ghetto that I am playing with badass chips like this but doing my own main() loop when this thing could run circles around my MSP430's with multiple threads if only I had an RTOS under the hood.
    intp | type 9w1 sp/sx/so

  8. #68
    resonance entropie's Avatar
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    That sounds like great work. Looking into that RTOS thing is intresting for me as well, I guess I'll try it as a new project on the MSP 430. I've been looking into building a more efficient CNC-control than my existing one. Atm I have a board controling the steppers via three L298 bridges, which are an energetic catastrophy. Only really works with a huge heat sink and a an extra fan :/. Plus the control needs an analog signal from the computer, which is impossible to generate regarding Realtime capability. I bought a 10 year old PC on ebay for 5 Euro, which was the only machine able to move my steppers at all via a somewhat realtime parallel port.

    Maybe with an RTOS sitting on the chip, I can control it digitally from the PC. That would be already possible with an AVR, but looking into that new chip would be more fun. Especially concerning all the additional gadgets it has. I am gonna take a look at the FreeRTOS windows emulator, gonna see how that works.

    Meanwhile I had my printrbot imported and assembled. Here are some first prints:



    I need a fan to cool the plastic while printing, its pretty non-heat resistant and the results aint too precise yet. With a fan tho that should be better. Printing is a lot of fun, you should really try it. PTC just released a free CAD-program and I'll use that to build some boxes for my electronic projects. Only the sky is the limit when it comes to finding ideas on what to print in that case
    [URL]https://www.youtube.com/watch?v=tEBvftJUwDw&t=0s[/URL]

  9. #69
    Senior Membrane spirilis's Avatar
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    Quote Originally Posted by entropie View Post
    That sounds like great work. Looking into that RTOS thing is intresting for me as well, I guess I'll try it as a new project on the MSP 430. I've been looking into building a more efficient CNC-control than my existing one. Atm I have a board controling the steppers via three L298 bridges, which are an energetic catastrophy. Only really works with a huge heat sink and a an extra fan :/. Plus the control needs an analog signal from the computer, which is impossible to generate regarding Realtime capability. I bought a 10 year old PC on ebay for 5 Euro, which was the only machine able to move my steppers at all via a somewhat realtime parallel port.

    Maybe with an RTOS sitting on the chip, I can control it digitally from the PC. That would be already possible with an AVR, but looking into that new chip would be more fun. Especially concerning all the additional gadgets it has. I am gonna take a look at the FreeRTOS windows emulator, gonna see how that works.

    Meanwhile I had my printrbot imported and assembled. Here are some first prints:



    I need a fan to cool the plastic while printing, its pretty non-heat resistant and the results aint too precise yet. With a fan tho that should be better. Printing is a lot of fun, you should really try it. PTC just released a free CAD-program and I'll use that to build some boxes for my electronic projects. Only the sky is the limit when it comes to finding ideas on what to print in that case
    So far it looks like FreeRTOS isn't much more than a simple scheduler and a library of code to implement reasonably canonical device drivers (queues, semaphores, etc)... so it's just a fancy addition to what we typically write on MCUs like the AVR and MSP430. I guess you could implement a lot on top of it and use it as the infrastructure for a far more sophisticated system employing TCP/IP, USB, etc... In any case I suspect using an RTOS platform is a small but useful step up in laying the foundation for your applications.

    Alas, a well thought out system to allow an MCU to control your CNC rig should be a boon no matter what (a PC twiddling its parallel port always screams "ghetto" to me ... lol), and an RTOS will probably help with that. Guess the big choices will involve how much RAM the mcu needs and that'll probably decide what kind of controller you use... MSP430's tend to be rather small although they just recently announced a new expansion of the "value line" series to 56K flash/4K SRAM, and the higher-end F5xxx series of MSP430 I think is less cost-effective for what you get (there's a thread about that here, good read.)

    It does sound like STM is really killing the market with their ARM-based MCUs. The STM hobbyists all seem to be more hardcore folks who do this stuff for a living though. My Renesas RX effort is a bit of a lark, I haven't found many folks at all who tinker with Renesas chips in their spare time... but the hardware is pretty comparable to what STM's put out at least. I have 2 Renesas boards laying around that have 96KB and 64KB RAM on them, respectively, and their later offerings go even higher.
    intp | type 9w1 sp/sx/so

  10. #70
    Senior Membrane spirilis's Avatar
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    I'm in for 2 of the new BeagleBone Black....
    http://beagleboard.org/Products/BeagleBone%20Black

    Somewhere I'd read it estimated that the CPU used in the BBBlack should be roughly 2x the performance of the Raspberry Pi's CPU. (edited) Looks like its GPU is about 1/2 the performance of the RPi's, at 20M-polygons/sec vs. RPi's 40. Not sure what that means in terms of actual media playback capability et al; the BBBone's is comparable to the iPhone 4 GPU I believe. Has microHDMI output with audio support soon (needs a driver update I think).
    Mine should ship 5/13. Includes a boatload of I/O on its headers; 5 UARTs, CAN, tons of GPIOs, an ADC onboard that works up to 1.8V (the rest of the I/O is 3.3V), etc. I'm gonna keep one for tinkering and one for projects... probably on my desk @ work as a low-power server. I have some ideas for building a remote RF-enabled terminal for carrying around the office.
    intp | type 9w1 sp/sx/so

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