Hi Leon,
if you design with a STM32F4xx and 100 pin, I would recommend to choose
one of the newer types (read STM32F469/STM32F479). They have a pinout
compatible to the 100 pin STM32F7xx line (and it is only slightly
different compared to the STM32F40x so a relayout shouldn't be hard).
With this it would be trivial to drop in a much higher performance
STM32F7xx without PCB redesign. The F7xx gives about twice as much
performance as the F4xx with about the same amount of power used (that
is our experience with the signal processing in the UHSDR/mcHF vs.
UHSDR/OVI40 firmware builds). This restriction does apply for 100pin
devices only. So if you used a 144 pin variant of the STM32F405, nothing
to worry about.
BTW, once the STM32H7 is really readily available, you get either even
more processing power at 400 Mhz clock for about the same power usage or
at the same clock rate similar performance but less power consumption
due to shrinked MCU design (90 -> 40nm AFAIR).
Danilo
On 09.03.2018 07:00, Leon Lessing wrote:
> Hi all,
>
> Just bear with me here,
> My experience with some of the brandmeister guys has been less than
> spectacular. There is no reason we cannot use "dmr framing" and use
> codec2 to transmit stuff, effectively splitting a dmr channel into 4
> potential codec2 slots.
>
> I have revamped the adf7021 hotspot thing so it is more rf friendly,
> the design is unfortunately in eagle 7.7, mail me for a copy.
>
> This week I have been on holiday and struggling with the lora issue,
> but in the back of my mind I have been thinking mmdvm, hotspot
> hardware adf7021, sm1000 and 1296. I am about 90% finished with a
> mmdvm/sm1000/sdcard hybrid using a stm32f405.
>
> The code from mmdvm_hs uses bit banging to talk to the adf7021, I will
> add an adf7021 to the mix and maybe a rda1846, a gps and esp8266.
> Another idea is to break out the extra control lines and spi bus from
> the stm32f405 to a connector so we can build a stacked system. I'll
> publish the pcbs, I have no idea how we can use git or svn to share
> the pcb work.
>
> There is issues with the adf7021 and harmonics, this is why the
> commercial market uses R5000 (dedicated dmr framing) and the CML data
> pump devices. Dual band matching seems to be an issue with this device
> as well, I am trying to get the hotspot hardware to work on 145Mhz
> without harmonics on 290Mhz.
>
> Please mail me if you need a copy of the files for a peer design
> review, I will use dirtypcbs to do the dev run and give you guys the
> links and you can order pcbs, shipping from South Africa is terribly
> expensive.
>
> Look at the pine64 as an alternative to raspberries. The idea of doing
> a sdr radio is excellent, but mixer bleed through is a massive issue
> for the transmitting side. (most mixers gives 60db local suppression,
> but 60db down on +5dbm local inject is still a very strong signal)
>
> Regards,
> Leon
>
>
>
>
> Leon Lessing
> 雷立安
> ZS6LMG/AC9GU
>
>
>
> On Fri, Mar 9, 2018 at 1:31 AM, Adrian Musceac <kanto...@gmail.com
> <mailto:kanto...@gmail.com>> wrote:
>
> Hi Alan,
>
> >
> > I ask, how far are we in being able to completely replace the
> firmware
> > in the lowly MD-380 and clone radios? Or, could we beef up the
> power in
> > the 7021, already used in the project!!!!!!
> >
> That (as in running Codec2 2400A) will never happen for technical
> reasons.
>
> Using an SDR it's possible to have Codec2, C4FM, D-Star, DMR and
> whatever else on a single device.
>
> There exist handheld full SDR terminals with a price point of
> $800-$1000, capable of running almost everything you want up to high
> speed video. Documentation is close to zero, writing software for them
> would cost in the high 6 digits figures (not going to happen soon).
> Said terminals will go EOL in 4-5 years as public services transition
> to LTE.
>
> If you want to try some of the new digital modes without spending a
> fortune in equipment and DSP training, I suggest to invest some time
> in learning GNU radio. It's the only viable alternative. I managed to
> make for myself 4 types of Codec2 VHF modems using it. BPSK, QPSK,
> 2FSK and 4FSK. Enough to play with for a while. OP25 (a GNU radio
> project) has had P25, C4FM, D-Star and DMR for a while now. Combining
> them into a single, easy to use application is just a matter of time.
>
> Cheers,
> Adrian
>
>
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