This will be a project that I outlined in an email to the SoftRock group. This is to be a low cost controller for the SI570 that requires no PC. Initial plans is to store a table of frequencies, the CPU will calculate the parameters for the SI570 itself.

It will in it's final form have the following features;

1. 16 bands and 4 LEDs to display in binary which band is active
2. Up to 64 frequencies in a band, with 6 LED bars to show the selection in binary.
3. Use of EEProm to remember last selection after powering the unit off.
4. Frequency stored as 4 bytes as the number of hertz, and bandpass filter information
5. Optional output pins to activate band relays.
6. Optional crystal with frequency trimmer instead of cheap resonator to have an accurate oscillator for counter feature.
7. Optional connection to a 2x16 display to display frequency.
8. Optional frequency counter mode if connected to a 2x16 display
9. Optional self calibrating, will read output of SI570 and adjust a SI570 compensating number to have the frequency be more accurate, no display required, but will require trimmed crystal.
10. Possibly bigger ATMega chip to accomodate optional features.
11. 2 to 4 buttons to select frequencies and modes

If options raise the price too much then I would implement options 6 and 9 foremost and the others as resources permit.

It consist initially of the following hardware;

1. ATMega88 CPU (28pin PDIP), later maybe switch to a ATMega48hich cost $1.60 in Qty 25 if it will fit in 4K of flash
2. A LED bar 10 segment bar graph for the display, 4 bars for the band information, 6 bars for the frequency in the band in binary form.
3. Optional 2x16 display.
4. A SI570 chip + miscellaneous components.

01/05/2008

I started this morning putting the hardware together and will try to communicate to it later today. I'm having problems with the development system not taking to the board, most likely it's a wiring problem, will continue tomorrow when I'm not so tired.

01/06/2008

After beating my head against a wall and getting nowhere, I could not find anything wrong with the CPU board  I decided to try a development board from Sparkfun so I can sort out where the problems are. Well, I can't talk to it either. I then tried a different compiler and IDE and it could not talk to the chip either so it seems I'm having a problem with my serial port. Everything else seems OK so I will have to dig out a laptop or something that has some serial ports. The PC I used is the only one that has a serial port. Iwas having problems prior to this talking to a PicAxe so now I know why. I will try a USB to serial adapter and see if that works(they rarely do for programming chips).

01/07/2007

It started acting up again then the PC would not boot turns out the serial port is fine it's the PC going of the deep end of ocean. It stopped booting but worse it had a BIOS error saying the Plug and Play could not enumerate the devices, sounds like a root cause. I changed some settings in the Bios and the error went away, but the PC would still not boot except in safe mode. Afer re-installing the Video, USB, and chipset drivers the PC settled down and seems fine.

Went back to working on the hardware and it's working fine I could download shoftware and run programs. Tomorrow is back to writing the software.

01/19/08

I have been pretty busy at work and had little time but some progress has been made;

I started evaluating different software development systems for the AVR chips not just for this project but it's something I needed to do anyway. There sure are a lot available. But I'm homming in on a few;

1. Bascom-AVR Basic compiler, it's reasonable ($99) generates fast code, but it's a little code hungry, it's binaries are a little bigger that the others, besides the price it has a lot of plusses. I supports a lot of data types including Double floats, has a library of tools to work with all sorts of devices, and it interfaces to PonyProg real well. Some advanced libraries are extra but reasonable.
2. MikroPascal Pascal compiler, cost about $150, generates the fastest and smallest code with the exception of MikroBasic compiler which generates a tiny bit smaller code. It has a very extensive library of routines to use the hardware features, no Double floats. Has Units for organizing the code.
3. MikroBasic same as above except it's Basic instead of Pascal
4. AVRco Pascal compiler, outrageous price ($650) but the demo version will do 8K of code, you can do an awful lot in that space,  generates slighly bigger code than the Bascom-AVR compiler, buying it is out of the question. It's library is huge, and even covers a lot of external chips. A huge plus is that it generates code with debugging information for the AVR studio debuggers.
5. GCC C development system, it's free, it will work in Windows or Linux, generates decent code, and debug information for the hardware debuggers. It has a big minus, it's C++ which I totally dislike and try to stay away from as much as possible( too many years trying to find pointer errors) . I have not tested this one yet.

All these development systems are either free of have functional demos that will allow enough code to give it a serious workout, so soon I will settle on one of them. In the meantime, systems 1 thru 4 have I2C libraries and in all four I was able to talk to the SI570 chip rather easily. They all have interfaces to serial ports, I2C, keypads, LCD displays, even Ethernet controllers so down the line I will see how that works out.

Yesterday I received a ICSP Programmer/JTag ICE debugger/DebugWire debugger and have been playing with it, I finally have it figured out after a lot of false starts and headaches, I even thought for a while that I had killed a couple of chips, it was the operator who was the troublemaker instead. I bought a second Programmer/Debugger (AVR Dragon) that can handle  all the programming and debugging schemes that the AVR chips use, but I need to buy some cables before I can use it. I also received some tiny AVR chips for use in the final project, they are cheap ($1.60), and in 14 pin DIP packages but have enough resources to do some serious applications.

Slow progress so far because I been playing with the toys instead of doing anything useful but all the pieces are falling into place, I'm starting to dissect how to calculate the parameters for the SI570 without using huge numbers But I'm having a lot of fun while doing it, that is except when I had problems with the debugger, that was no fun, but all is well now.

Useful links;

www.mcselec.com/index.php

www.e-lab.de/AVRco/index_en.html

www.mikroe.com/en/compilers/mikropascal/avr/

www.mikroe.com/en/compilers/mikrobasic/avr/

www.lancos.com/prog.html