Minima - Software Progress 2

Current State

Updated: Aug 7, 2014 11:26
Updated: Aug 9, 2014 18:32
Updated: Aug 14, 2014 18:20
Updated: Aug 20, 2014 21:59
Updated: Sep 1, 2014 06:44
Updated: Sep 23, 2014 10:12

See the next post for help text, and here for a users successful build.

The additional functions that my Minima Alternate Tuning Method Repository provides are as following.

• High resolution, plus/minus 1Hz Tuning (thanks to Jeff - KO7M).
• Near Normal Dial Tuning Method as found on most Dial Radio system.
• Support for six additional buttons
• Tuning Cursor positioning via Left/Right push buttons.
• Automatic (original) or Manual Selection of Sideband via push button.
• Ham Band Switching via Up and Down push buttons
• Nine Ham Band Memories, with Frequency and Sideband Saved
• Two Memories for each Band, implemented and saved as "A" and "B" VFO
• RF386 Power Amplifier Filter Selection via generated clock pulses on PD7 (pin13).  Note: It works now, with new revised timing pulses.
• Tuning by 2500Hz Steps (similar to FT-817, mode set via button 7)
• Re-Center Tuning Knob while any Button, Key, or PTT is pressed, without changing the Freq
• RIT Mode, implemented as +-990Hz in 10Hz Steps
• Limit TX to within the Ham Bands (currently, the user must control Sidebands out side of the Ham Bands)
• Include Jeff -KO7M Si570 Driver "Tuning Click Fix"
• Frequency Dial Calibration via IF Frequency Adjustment
• IF Configuration and Adjustments
• On demand, save user specified Band Memories into non-volatile memory, and retrieved on power up.
• Factory Reset - By Holding any Button at Power-ON or Processor Reset
• Split, Cross-Band or In-Band operations; Transmit on "A" VFO and Receive on "B" VFO (Note: I need to check the Regulations to see if Split operations is legal on HF?)
• Automatic CW ID and/or CW CQ Calling Memories.
• Two CW Macros and Two QRSS Macros Beacon
• User Preference Menu Edit Mode

The software can be access at:

https://github.com/wa0uwh/radiono_erb/

Some Plans

Additional functions that are currently being planned, are:

• Implement option for UK Band Limits and Default Frequencies

Long Term Plans

Some longer term implementation ideas include:

• Implement WSPR, and PropNET Transmit Beacon modes.
• Limits imposed on modes, based on Band Plans, i.e., SSB Transmit only in phone section. A "digital" mode could allow computer controlled transmit via a sound card on Upper Sideband.
• etc, etc

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Minima - Proposed New Tuning Method

This post is for a few brave (adventuresome) Minima builders/users. This is a "work in progress" and therefore feedback is requested.

Although I have not completed my experimental Minima Transceiver build, I have built the Digital Control Module and have been working on the Arduino software that controls the Display and the rest of the Minima hardware. See my previous blog posts, or at:

http://wa0uwh.blogspot.com/search/label/Minima

Minima Digital Control and VFO Module
Running REV 0.4.erb

One of the modification that I have made is to incorporate Jeff's (KO7M) 1Hz Driver for the Si570. This modification allows for 1Hz Tuning of the my Minima's VFO. Jeff's Si570 code is available on GIT Hub at:

https://github.com/ko7m/Si570

Also, I have been working to modify the Arduino Sketch to provide an Alternate Tuning Method, what I consider a "Near-Normal" tuning method or functionality, for the original Farhan's Minima circuit and hardware. With only the original circuit's tuning POT to work with, functionality is of course somewhat limited.

The original Minima Arduino Sketch (REV 0.4) changes frequency via the Tuning Pot and pre-programmed steps. Tuning rate is dependent on how far from the "center of rotation" the Tuning Pot is turned. To tune "up and down" around a received signal the Tuning Pot must be turned past the Pot's center location, which of course is not typical of a normal receiver. Farhan's original Minima Arduino Sketch (REV 0.4) is available at:

https://github.com/afarhan/radiono

The original Minima Arduino Sketch of VERY functional. But, I as programmer, and like they say: "programmers will be programmers, and they will modify programs", so, I am, what I am  :-)

My goal for this program modification is to maintain the functionality of the original Minima Arduino Sketch and incorporated Jeff's Integer Si570 Driver, which provides High Resolution Tuning (< 1Hz).

My modified Sketch, can replace the original Minima Sketch (REV 0.4) via a normal Arduino IDE compile and download. And if needed, the original Sketch can be re-installed via the same method.

This modified Minima Sketch (REV 0.4.erb) is available on my GIT Hub, at:

https://github.com/wa0uwh/radiono_erb/

This revision ALSO provides the following:

• This Sketch can be used in place of original Minima REV 0.4 Sketch (but of course, use at your own risk).
• Provides Eight Digits for Frequency Display
• Provides 1Hz Tuning Resolution

     Provides a Near-Normal Tuning Method

• Tuning is accomplished by moving the cursor via the Tuning Pot to the digit that you want to change.
• Then wait for the underline cursor to start flashing.
• Then change the digit by turning the Pot left for lower, and right for higher frequency.
• Near the Stops (the Pot rotational Stops) the digit will change automatically.
• At the Stops, the digit automatically changes even faster.

After you stop Tuning (i.e., stop changing the digit), the mode switches back to "cursor move mode" for a few seconds, as indicated by the Non-blinking Cursor, then repeats.

• The cursor can be "parked" to the right of the least digit.

The current Mode is indicated by the cursor style:

• Blinking Underline Cursor = Digit Change Mode
• Non-Blinking Underline Cursor = Cursor Move Mode

These modes are ALSO indicated by the far right character on the top line:

• "*" = Cursor Move Mode
• "-" = Digit Change Mode
• "<" = Digit Changing to lower frequency
• ">" = Digit Changing to hight frequency

Note: If the Cursor Move Mode seems to get lost, move the cursor to each of the two hard Stops to recalibrate cursor movement.

Some new functions on my To-Do list include:

• Stay Compatable with Original Minima Hardware
• Provide for Rolling Menus
• Band Pick from Menus
• User Defined Frequency Memories
• User Defined Frequency Tuning Steps (e.g. similar to FT-817's 2.5KHz steps)
• Transmit Macro (send CW CQ, ID or more)
• Transmit Mode from Menu
• Beacon Modes: CW, QRSS, and WSPR-Tx
• User Defined Operational Preferences; Digit Count, Tuning Rate, etc
• etc

If you try this initial experimental "REV 0.4.erb", I hope you find it useful.


Have fun !!
and, Provide Feedback !!

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UPDATE
Git Hub Repository URL's have been corrected.


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Minima - VFO Troubleshooting - Cont'd 3

After four days of extreme frustration, while troubleshooting my Minima VFO Module (see previous posts), there is success!

My friend Jeff - KO7M came by today with known working tools (BusPirate) and parts (Si570). We had been troubleshooting my VFO problem via e-mail and over the phone, but we were not getting anywhere.

Jeff at the Microscope

The problem came down to, two (2) simultaneous failures, one in my BusPirate (BP) and one in my VFO Module that I was testing.

1. My BusPirate fails to generate I2C SCL (clock) signals, even though many other functions seamed to work. Without an SCL signal data can not be received by a Device Under Test (DUT), even though the BP can receive Data using the same SCL wire from the DUT.

2. The failure of my VFO was the Si570 itself, it would not accept I2C data or commands, even though it produced RF on the output. It is DEAD.

Before Today

Before today, I had created an Si570 BreakOut Board (see previous post), with just the Si570 and Header pins. My intent was to verify that the BP was working as expected, but because there are also wires, clips and connectors that could have failed results were inconclusive.

Si570 Breakout Board

Si570 Breadout Board

At this point I still could not determine if the failure was in the BP or had I damaged another Si570. So, I built a second Si570 Breakout Board. But alas, still nothing seemed to work.

Today - Jeff to the Rescue !

With Jeff's known working BP we quickly determined my VFO Module (i.e. Si570) was bad. Other I2C devices; the two Si570 Breakout Boards and a Real Time Clock Module (RTC) all work as expected.

Because yesterday I had used my last Si570 on the second Si570 Breakout Board, I could not repair the VFO Module. but we could build an Si570 Breadout Board Adapter  that connects between the Breakout Board to the Minima CPU Module. I had previously designed and did a layout for the Adapter with DipTrace, for just such an occasion. We spent the rest of the afternoon building and testing the Adapter Board.

The Adapter Board tested correctly with Jeff's BP as we hoped. It also tested and worked with the Minima CPU Module.

Adapter Board Connected to the Minima CPU
and a Coax Cable, the Si570 Breakout Board in the Foreground

Stacked and Ready for Testing

Now all Minima Modules worked as expected, we checked for a varying frequency while tuning, we estimated on the oscilloscope 20MHz at the low end, and 50MHz and the high end while Tuning across the (0-30MHz) HF band (for a 20MHz IF).

34.2MHz  (14.2+20) As Shown
with 10X Expanded Sweep Scale

Minima CPU Module and
Temporary VFO Module 

I am a happy camper - Thanks Jeff, for the help !


I can now continue my experiment Minima Transceiver Project.

I need to order a few more Si570's, and a new BusPirate (or troubleshoot and fix it).

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Minima - VFO Troubleshooting - Cont'd 2

Well, that did not work, see previous post.

I created a Si570 BreakOut Board with minimal configuration to have something that I can test and verify my BusPirate. I got the same results with the new board, the I2C Address Scan returns nothing.

I must have something wrong with my use of the BusPirate.

The Si570 BreakOut Board that I created is a little different than previously posted, it now will fit in a standard 600mil socket. Which means that it is a little bigger than the original 500mil config, but should be more useful.

Here are some of the build details.

The New 600 mil Layout
As Designed with DipTrace

The size of the board is about 0.5x0.7 inches and is 0.032 inches thick, with four via's (40mil pads, 10mil holes).

You can almost see through the PCB material, the two sided image alignment is reasonable.

A Panel of 
Double Sided Toner Transfer PCB's after Etch
(Showing the Back Side)

This is the results after: Cut, Solder Wipe, Holes Drilled, and Parts Loaded.

The Finished Si570 BreakOut Board

When I get the BusPirate operational issue sorted out, this should provide a simple verification test. It will also be a useful part for ProtoBoard experiments.

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Minima - VFO Troubleshooting - Cont'd

Regardless of what I have tried, my Minima VFO Module does not seem to work, see previous post.  It does not respond to a simple I2C Address Scan from the BusPirate (BP). The problem could be a something simple on the VFO Module, a dead Chip,  the BP, or the connecting wires. I could test the BP and wires if I had a known working I2C device, but I don't.

To fix that, I am going to build a simple stand alone Si570 BreakOut Board, which will only contain an Si570 and Header Pins. If this works, it will be useful for verifying my BP and also it will be useful for other standard ProtoBoard experiments.

Proposed Si570 BreakOut Board

A simple Google search did not suggest a consensus of pin outs for a breakout board, I decided to arrange the pin in Si570 documented order similar to a DIP. The board will be about 0.5x0.6 inches. I guess I should have made the pin row spacing 600mils (not 500mils) so it would fit standard PCB DIP Sockets.

Using standard pin order requires a trace on the backside with the accompanying two via's. Two additional via's will help tie the front and back ground planes together. All soldering for the Headers will be done on the top side, because Homebrew boards do not have plated through holes, and therefore it would be difficult to solder under the Headers on the back side.

I could have included the two required I2C Pullup Resistors, but no, I wanted this to be a generic as possible.

This maybe a very useful board for my future projects, it is a simple task to make several copies while making the first, using the Toner Transfer (TT) Method.

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Minima VFO - Under the Microscope

I have been doing some troubleshooting of my Minima VFO, for some reason it is not "talking" with my Minima CPU module. My friend Jeff - KO7M as provided some suggestions for resolution that I am working on.

My Minima VFO
As Built

Just for fun, I took some Microscope Photos while reviewing the circuit and PCB layout for errors. Here are a few for your review.

Si570
From Pins 4 and 5 Perspective

The 3.3 Volt Regulator - SOT-89-3
and Its Output 0805 Filter Caps

Power Indicator with its attending limiting Resistor
The Resistor and LED are size 0603

Binocular Core Output Transformer
This is 32 AWG Wire

SMA RF Output Connector

I enjoy working under the Microscope, there are many things that otherwise we would not see.

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Si5351A Circuit Build - Success

After the Failure as described in previous post, I modifying my Si5351A VFO PCB layout for proper Crystal Pad Pattern, and finished the build.

This circuit will be used as a LAB Test Oscillator and for my experimental Farhan Transceiver VFO and BFO.

Si5351A Module Ready For Test

The 3.3Volt Regulator is the black chip next to the top pin of the power header, the black chip near the bottom header pin is the Si5351A, and below that is the very small 27MHz Reference Crystal. The three BN-47-2402 Binocular Cores provide ground loop isolation for each of the SMA RF Connectors.

Si5351A and Si570 Modules
Ready for Use

One unfortunate aspect of both of these modules is; the Si570 and Si5351A chips do not have options for changing their I2C access address. And therefore, only one of each can be connected to single I2C control circuit without a special I2C switch.

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Minima - VCO Module

New Toner Transfer Paper was received and Ferric Chloride Gremlins are at bay. See previous post.

Without too much difficultly, I finished my Minima VFO Module (see description and PCB Layout on previous post). Currently I do not have a way to program the Si570, but with power connected, the Module outputs its default RF signal.

The board is 1.0 x 1.2 inches, the homebrew vias are 40 mil pads with 12 mil holes. Solder Wipe was used for copper protection.

Minima - Si570 VFO

Backside Traces

As stated in the previous post, I modified Farhan's original circuit to include an output transformer, I want to also use this circuit as a Generic Lab Test Bench RF source where DC Ground isolation would be useful. The output transformer was wound as a 4:4 turns on BN-47-2402 core.

I plan to create an equivalent circuit using the Si5351 chip (as previously posted). It will look similar to this board, but it will have three output SMA connectors.


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Signal Generation

I have been watching Jeff's - KO7M Blog and his current QRSS/WSPR Transmitter project using the DDS-60 as part of the prototype. Jeff had previously done some work with the AD5330 8 bit DAC.

Jeff's efforts have inspired me to look at a previous purchased Si750 SDR-Kit, that I still had not built.

Without much difficulty, I now have put the Si570 SDR-Kit together (only the 3.3v Regulator went in backwards, which I fixed). Testing is still in progress.

While investigating; the kit's circuit and the Si570 datasheet, the DDS-60 and its AD9851 device, I have learned a lot more about micro-controlled frequency generators and DDS's in general.

This may be Old Stuff for some folks, but this is what I have learned, this info is saved here for my future use:

The Si570

The Si750 SDR-Kit is a real neat device with a very wide frequency range of 10MHz to >900MHz and can be controlled via a two wire computer connection (I²C). It's output is square-wave, which is ideal for a mixer LO of a receiver

But, the Si570 has some limitations for use as a general use signal source. The output (square-wave) would require difficult frequency sensitive filtering to obtain a clean sine wave over the entire frequency range.

Obviously for a single frequency, a filter can be easily created, but for that single frequency, a simpler crystal or oscillator circuit could be used instead. 

Once setup, the Si570 output is continuious, without assistance from the computer or micro controller. 

The DDS-60 

More information needed.

The AD5330 

The AD5330 8 bit DAC is a general purpose signal/wave-form source with a frequency range of 1kHz to 36kHz. It uses DDS processor to create the output wave form. Almost any shape of output can be created.

For use as a AF signal source, it's output is normally a stepped waveform, which normally needs a low pass filter to remove the steps.The output can be used with a mixer to create double sideband signals. 

A continuous use computer or micro controller is needed to generate the steps of the intended frequency or wave form.

I need to explore these circuits more, and will update as necessary.

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