I now have an Intronics Pocket Romulator model 1 in hand. As luck had it, the company was local so I drove over and got one on lunch. The problem is I need a ROM reader and I don't yet have one. Do you are anyone have a binary or hex image of one of the 2k X9000 EEPROMS? I'm continuing to read up on it and my understanding is I would load the file into it then it will allow live editing of the EEPROM image byte by byte. Probably a dumb purchase but whatever....
On Mon, Aug 8, 2022 at 2:21 PM Dennis Boone <
drb@...> wrote:
?> I assumed for whatever reason, the radio just iterated over the mode
?> data again and again refreshing itself to make sure nothing was
?> inadvertently corrupted along the way. I guess I got this mental
?> picture from the synth refresh description and likely incorrectly
?> applied it to everything else.
Remember that the 9000 radio has only 256 bytes of RAM (minus
microcontroller control registers which are memory mapped), into which
it has to stuff the currently needed mode data, software stack, counters
and control and status values for loops and whatever, etc.
The X has _64_ bytes.
It's pulling in the data for the mode it needs now, and keeping whatever
bits it'll reuse in RAM -- maybe the whole mode, maybe just some of it.
Without disassembling the ROMs, we don't know if it stores two whole
modes for scan, or just one and a "go back to" mode number.
In the X, the processor generates the tx PL/DPL data, and counts the rx.
I can't speak to whether it repeatedly reprograms the prescaler /
divider setup.
?> So, how do you suspect scan works? You are saying the radio reads the
?> modes into the uP from the EEPROM all at once along with the PL data
?> then executes operations using that data stored internally?
This is a pretty good description of the scan concepts for the X:
Since the scan data is encoded in the mode data (primary and secondary
priority scan as numbers, and non-priority scan list as a bit map), the
radio must be reading each mode as the list calls for it, and
remembering somehow how to get back to whence it came.? The X _could_
just be reading the Mode Select lines from the control head each cycle,
or it could store the mode number.? Either way, with such a small RAM, I
rather doubt it'd keeping more than one mode worth of data in RAM.? Note
that on the X, for some scan modes, scan mode data is held *in modes
other than the currently selected receive mode*.
I rather expect the cycle looks something like:
- fetch scan target mode data (pri1, then pri2, then scan list)
- change frequency to there
- check for signal, maybe stay around for a bit
- maybe switch back to the selected mode by
? - fetch selected mode data
? - change frequency to there
- repeat
De
