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<font size="-1">Hey Dan,<br>
<br>
Thanks for the clear explanation!<br>
<br>
--David<br>
<br>
</font><br>
<div class="moz-cite-prefix">On 09/13/2015 09:28 AM, Dan Smith
wrote:<br>
</div>
<blockquote cite="mid:55F5A441.3060207@danplanet.com" type="cite">
<blockquote type="cite">
<pre wrap="">Ok, thanks for the confirmation on what Chirp does today. I am curious
though if what Chirp downloads as an img from the radio is the complete
radio image? If it is a complete image yet it only modifies the
channel/freq/features areas, there still might be some hope that
someday, a "very advanced" area could be added to flip these specific bits.
</pre>
</blockquote>
<pre wrap="">
I think you're probably misunderstanding how these devices are laid out.
Most of these single-chip radios are laid out with the following components:
1. A CPU, with some non-volatile firmware
2. An eeprom or flash memory array
3. The single-chip radio
firmware
^
|
flash <-----> CPU <-----> radio
|
serial port
|
computer
The programming mode we have access to merely uploads and downloads
ranges from #2. We don't get to access or change the firmware bit, and
we certainly don't get to talk to the radio chip directly. The CPU could
load some settings from the memory array and program the radio chip at
startup, but I think it's unlikely. If it does, it would be pretty
difficult to find this without some help or documentation. Regardless,
it would be limited to whatever settings and values the firmware is
designed to program the radio with. When we're in programming mode, we
just have two commands: "write $blob to location $foo" and "read
location $foo". The "image" we download is merely "every memory location
from zero to end".
</pre>
<blockquote type="cite">
<pre wrap="">While I'm at it, I'm curious what people think about this specific 9600
baud hack that this HAM did. In an analog radio, one would need to tap
into the discriminator to get a wide enough & flat pass
band to support FSK over FM. Since these Baofeng radios are SDRs and
pack everything into a few ASICs, I don't know if getting into this
stage of the radio block is required anymore.
</pre>
</blockquote>
<pre wrap="">
This is pretty off-topic for this list, so you should probably take it
elsewhere.</pre>
</blockquote>
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