Author Topic: GPSDO project in Silicon Chip magazine (Oct 2018)  (Read 1565 times)

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Offline intabitsTopic starter

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GPSDO project in Silicon Chip magazine (Oct 2018)
« on: October 20, 2018, 02:02:01 pm »
There've been a few threads recently about GPS disciplined oscillators, and I expected that someone might have mentioned a GPSDO project starting in the current issue of Silicon Chip magazine, but I can't find any references to it, so I'm making one here.

I won't try to describe it's features, as that is better done by the first two pages of the part 1 article, which can be seen here:-
http://www.siliconchip.com.au/Issue/2018/October
(clink on the article link #5 at the left)
« Last Edit: October 20, 2018, 07:43:33 pm by intabits »
 

Offline Gyro

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Re: GPSDO project in Silicon Chip magazine (Oct 2018)
« Reply #1 on: October 21, 2018, 10:47:06 am »
Unfortunately, when you look at the 'shopping list' down at the bottom of the left hand pane ('Micromite backpack' etc), it starts to look expensive.

The biggest issue I see is the non-availabilty of source code - programmed device or Hex file only, that limits understanding and no ability to modify.
Best Regards, Chris
 

Offline jpb

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Re: GPSDO project in Silicon Chip magazine (Oct 2018)
« Reply #2 on: October 21, 2018, 12:56:05 pm »
Unfortunately, when you look at the 'shopping list' down at the bottom of the left hand pane ('Micromite backpack' etc), it starts to look expensive.

The biggest issue I see is the non-availabilty of source code - programmed device or Hex file only, that limits understanding and no ability to modify.
One difficulty with publishing a design in a magazine is that you need to use new, available components which means you're restricted to using a TCXO and then building an oven for it to keep costs down.

The advantage of a DIY approach (such as Lars) is that you're free to use OCXOs from  ebay which are much cheaper than their new counterparts.

The presence of cheap GPSDO units on ebay means that the main purpose of building one is educational, to tailor the design and have fun. I agree with you that a key part of building one published in a magazine is to be also able to experiment so access to source code is important.
 

Offline floobydust

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Re: GPSDO project in Silicon Chip magazine (Oct 2018)
« Reply #3 on: October 21, 2018, 05:24:43 pm »
Are we sure the (app) source code is closed? The S/W link is confusing:

Firmware (HEX) files and BASIC/C source code for the GPS-Synched Frequency Reference [0410718A.hex]
Firmware (with pre-loaded BASIC code) and BASIC source code for the GPS-Synched Frequency Reference.
Includes Micromite firmware v5.04.
Inside the download package you will also find the MPLAB X project and C source code for the required CFUNCTIONs.

Micromite interpreter firmware for MMBASIC is pre-compiled. Maybe C was used for the algo and then linked in to MMBasic?
 

Offline Gyro

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Re: GPSDO project in Silicon Chip magazine (Oct 2018)
« Reply #4 on: October 21, 2018, 06:12:11 pm »
Ah, that's better then!
Best Regards, Chris
 

Offline intabitsTopic starter

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Re: GPSDO project in Silicon Chip magazine (Oct 2018)
« Reply #5 on: October 22, 2018, 04:07:48 am »
Unfortunately, when you look at the 'shopping list' down at the bottom of the left hand pane ('Micromite backpack' etc), it starts to look expensive.

I plan on using my own controller, so I only need the analog/oscillator sections in the top part of the block diagram.
I've ordered the parts for those, came to around AU$68 (for TWO sets).
 


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