Hey everyone! It's been a while since I last posted in this thread, but I was working on a schematic/PCB for my version of the GPSDO and got sidetracked with life, the pandemic, etc.
Anyway, I'm hoping to finally get my boards sent off to the fab, but I'd love for the community here to take one more look at my schematic & board to make sure nothing looks majorly out of place.
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Hey everyone! It's been a while since I last posted in this thread, but I was working on a schematic/PCB for my version of the GPSDO and got sidetracked with life, the pandemic, etc.
Anyway, I'm hoping to finally get my boards sent off to the fab, but I'd love for the community here to take one more look at my schematic & board to make sure nothing looks majorly out of place.
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Hi Axel, and first: thank you. A question: it seems you are connecting the MCU serial port to the GPS module, unlike Lars' original schematic. But there is no provision in Lars' original code to communicate with the GPS, or to indicate a status on any of the extra LEDs you have included. Do you have an extended version of the Lars' GPSDO firmware to go with your schematic?
Two more little details: OSC_CTRL from the DAC is drawn as an input but it is really an output, ditto for the LEDs and the MCU UART Tx; and the RST(inverted) bus is not connected to anything (as far as I can tell).
The PCB looks very well laid out, with just one little detail that I would change if possible: TP1 (GPS PPS) would be under the GPS module if the module is mounted horizontally, can it be moved someplace else?
Had to make a decent amount of changes to account for the current chip shortage, but everything should be in stock with this version and the total comes into around $60 which is fantastic for a GPSDO in my book.
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I just want a cheap GPSDO for aligning some radios.
Had to make a decent amount of changes to account for the current chip shortage, but everything should be in stock with this version and the total comes into around $60 which is fantastic for a GPSDO in my book.
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I just want a cheap GPSDO for aligning some radios.When you say total $60 is that GPS antenna, GPS module, OCXO, populated PCB, power supply, suitable enclosure? I costed out my GPSDO design (which BTW decodes all NMEA and can do NMEA passthru) for an OCXO and populated PCB at less than $12US. But once you add GPS antenna $12, GPS module $6, enclosure $4, wall wart (will work off a $5 USB charger so say $5 although usually there's a better spare one somewhere) and serial/USB converter the total blows out to nearer $40.
I'm surprised nobody pointed out that my amplifier design for the 10MHz output was totally incorrect oh well - I bodged it into a unity gain buffer and all is well.
I've got the board assembled and it's up and running. Next plan is writing up the software. Is there a "recommended" arduino sketch for the GPSDO, or is everyone pretty much rolling their own based on the original document?
I'm surprised nobody pointed out that my amplifier design for the 10MHz output was totally incorrect oh well - I bodged it into a unity gain buffer and all is well.
I've got the board assembled and it's up and running. Next plan is writing up the software. Is there a "recommended" arduino sketch for the GPSDO, or is everyone pretty much rolling their own based on the original document?
The software in Lars first post is not bound to GPL v3.
Could be used as ie. lgpl or the like
/Bingo
Btw now that Lars' files are on GitHub under a GPL V3 license and under his copyright, I would question the ethics of anybody claiming the copyrights of the same or modified files or any change in the applicable open source license (in other words, changing from GPL V3 to any other license).
The software in Lars first post is not bound to GPL v3.
Could be used as ie. lgpl or the like
/Bingo
Lars did not specify any open source license for any part of his work before he passed away, and very modestly did not even reserve any copyrights. I had to assume his wish was to make all parts of his GPSDO design, including the firmware, available to any other person without any restrictions apart from retaining the "openness" and the fact that he is the original author, as the name of the project clearly indicates ("Lars' DIY GPSDO"). Hence the choice of the GPLV3 license for the files on GitHub. I believe this respects most closely the spirit with which Lars posted the project files here on the EEVblog forum.
The LGPL is a different license primarily used for software libraries. It's not really suitable for a project such as Lars' DIY GPSDO.
Btw now that Lars' files are on GitHub under a GPL V3 license and under his copyright, I would question the ethics of anybody claiming the copyrights of the same or modified files or any change in the applicable open source license (in other words, changing from GPL V3 to any other license).
If anybody here is in doubt about what all this means or wants to know the nitty-gritty, please check: https://opensource.org/licenses
Nobody would be claiming anything, they're just not bound to adhere to your gpl v3 license invention , if using Lars original sources.
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/Bingo
I consider the GPLv3 very restrictive and demanding. Knowing nothing about what the original author intended, this is not the license I'd have chosen.
What would happen if somebody in this threador elsewhere claimed the copyright over Lars' work for himself,and/or decided to change the license to a restrictive one,with royalties and fines?
You just did
Got my GPSDO board assembled, and it's up and running. For the most part at least. OCXO is alive, the MCU is programmable via USB, and nothing has let the smoke out yet.
However, it looks like the 32u4 with the Pro Micro bootloader doesn't like the interrupt that Lars used for the PPS signal.
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3248 -431 41681 6.3 NoLock 6 360 32 1 28109 56 1103 0 0 0
3249 -427 41680 6.3 NoLock 4 400 32 1 28109 59 1104 0 0 0
3250 -422 41681 6.3 NoLock 5 460 32 1 28109 63 1105 0 0 0
3251 -418 41682 6.3 NoLock 4 510 32 1 28109 65 1106 0 0 0
3252 -413 41682 6.3 NoLock 4 560 32 1 28109 69 1107 0 0 0
3253 -407 41684 6.3 NoLock 6 630 32 1 28110 74 1108 0 0 0
3254 -404 41684 6.3 NoLock 4 670 32 1 28110 78 1109 0 0 0
3255 -399 41684 6.3 NoLock 4 720 32 1 28110 80 1110 0 0 0
3256 -395 41684 6.3 NoLock 4 770 32 1 28110 83 1111 0 0 0
3257 -390 41686 6.3 NoLock 5 830 32 1 28110 88 1112 0 0 0
3258 -387 41685 6.3 NoLock 3 860 32 1 28110 90 1113 0 0 0
3259 -382 41685 6.3 NoLock 4 910 32 1 28110 93 1114 0 0 0
3260 -375 41688 6.3 NoLock 7 990 32 1 28110 98 1115 0 0 0
3261 -373 41688 6.3 NoLock 3 1020 32 1 28111 101 1116 0 0 0
3262 -368 41688 6.3 NoLock 4 1070 32 1 28111 104 1117 0 0 0
3263 -364 41689 6.3 NoLock 4 1120 32 1 28111 107 1118 0 0 0
3264 -360 41689 6.4 NoLock 4 1160 32 1 28111 110 1119 0 0 0
3265 -355 41691 6.4 NoLock 5 1220 32 1 28111 114 1120 0 0 0
3266 -351 41691 6.4 NoLock 4 1260 32 1 28111 117 1121 0 0 0
3267 -347 41692 6.3 NoLock 4 1310 32 1 28111 120 1122 0 0 0
3268 -343 41692 6.4 NoLock 4 1350 32 1 28111 123 1123 0 0 0
3269 -339 41693 6.3 NoLock 4 1400 32 1 28111 127 1124 0 0 0
3270 -334 41694 6.3 NoLock 4 1450 32 1 28112 129 1125 0 0 0
3271 -331 41694 6.4 NoLock 4 1490 32 1 28112 133 1126 0 0 0
3272 -326 41695 6.3 NoLock 4 1540 32 1 28112 136 1127 0 0 0
3273 -322 41697 6.3 NoLock 5 1590 32 1 28112 138 1128 0 0 0
3274 -319 41696 6.4 NoLock 3 1620 32 1 28112 142 1129 0 0 0
3275 -314 41698 6.3 NoLock 5 1680 32 1 28112 146 1130 0 0 0
3276 -310 41699 6.3 NoLock 4 1720 32 1 28112 149 1131 0 0 0
3277 -306 41699 6.3 NoLock 4 1760 32 1 28112 151 1132 0 0 0
3278 -304 41699 6.3 NoLock 3 1790 32 1 28113 154 1133 0 0 0
3279 -298 41701 6.3 NoLock 5 1850 32 1 28113 159 1134 0 0 0
h1 diff_ns: 1550 ppb average
h65535 diff_ns: -990 ppb average
VCO Range (ppb) = 2540 ppb
Gain = 65535 / VCO Range = 25.80
The internal voltage reference options may not be used if an external reference voltage is being applied to the AREF pin.
2111 -405 42168 29.6 NoLock 2 660 32 1 24262 80 10 0 0 0.0
2112 -405 42164 29.6 NoLock 0 660 32 1 24262 79 11 0 0 0.0
2113 -403 42162 29.6 NoLock 2 680 32 1 24262 81 12 0 0 0.0
2114 -402 42159 29.6 NoLock 1 690 32 1 24262 81 13 0 0 0.0
2115 -400 42157 29.1 NoLock 2 710 32 1 24262 83 14 0 0 0.0
2116 -400 42154 29.6 NoLock 0 710 32 1 24262 83 15 0 0 0.0
2117 -399 42151 29.6 NoLock 1 720 32 1 24262 83 16 0 0 0.0
2118 -398 42149 29.6 NoLock 2 740 32 1 24262 85 17 0 0 0.0
2119 -396 42147 29.6 NoLock 2 760 32 1 24262 85 18 0 0 0.0
2120 -394 42145 29.6 NoLock 2 780 32 1 24262 87 19 0 0 0.0
2121 -395 42141 29.1 NoLock -1 770 32 1 24262 87 20 0 0 0.0
2122 -393 42139 29.6 NoLock 2 790 32 1 24262 88 21 0 0 0.0
2123 -393 42135 29.6 NoLock 0 790 32 1 24262 89 22 0 0 0.0
2124 -391 42133 29.6 NoLock 2 810 32 1 24262 89 23 0 0 0.0
2125 -391 42130 29.1 NoLock 0 810 32 1 24262 90 24 0 0 0.0
2126 -390 42128 29.6 NoLock 2 830 32 1 24262 90 25 0 0 0.0