Potential DATV settop box project (aka the Ryde project)

Discussions about the new Ryde "Set-top Box" Style Digital ATV Receiver
YL3AKC
Posts: 41
Joined: Wed Aug 08, 2018 8:42 am

Re: Potential DATV settop box project (aka the Ryde project)

Post by YL3AKC » Wed May 20, 2020 8:28 pm

g0mjw wrote:
Wed May 20, 2020 8:09 pm
If height is an issue the flat nim version might be the best. There is an accurate mechanical drawing in the data sheet.
I already have two horizontal NIMs and made some "measurements by eye". Looks like NIM can be located on RPi3 on top of USB sockets, but this only simple fit test without any careful measurements.

PS: As I mentionet before, for online instannt brainstoriming you are welcome to telegram channel: https://t.me/Ham_DVBS_IRD
Janis, YL3AKC

g8gtz
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Joined: Wed Apr 07, 2010 6:26 pm

Re: Potential DATV settop box project (aka the Ryde project)

Post by g8gtz » Wed May 20, 2020 8:51 pm

If height is an issue the flat nim version might be the best. There is an accurate mechanical drawing in the data sheet.
As Janis said in an earlier post the horizontal NIM are much more expensive and harder to source - besides BATC still has 100 of the vertical type so maybe best to avoid that if possible ;)

Noel

g0mjw
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Joined: Sat Sep 20, 2014 9:15 am

Re: Potential DATV settop box project (aka the Ryde project)

Post by g0mjw » Wed May 20, 2020 8:59 pm

I thought the SERIT NIM already outputs the TS? We just need to find a way to read it in.

Its in an 11 bit parallel format, 8 bits data plus sync, valid and clock. In the minitiouner a 74HC10 chip gates the the TSValid / TSError / TSClock signals. The remaining control signals are slower, I2C, reset.



https://wiki.batc.org.uk/images/6/6d/SERIF.pdf

Mike
Last edited by g0mjw on Wed May 20, 2020 9:17 pm, edited 1 time in total.

g0mjw
Posts: 1371
Joined: Sat Sep 20, 2014 9:15 am

Re: Potential DATV settop box project (aka the Ryde project)

Post by g0mjw » Wed May 20, 2020 9:00 pm

g8gtz wrote:
Wed May 20, 2020 8:51 pm
If height is an issue the flat nim version might be the best. There is an accurate mechanical drawing in the data sheet.
As Janis said in an earlier post the horizontal NIM are much more expensive and harder to source - besides BATC still has 100 of the vertical type so maybe best to avoid that if possible ;)

Noel
Well we could always make the socket horizontal.

However, I think a separate PCB might be better as that allows for later PIs or other boards. Basically a V2 like board but updates with a pair of parallel to serial interfaces instead of the FTDI module. One of those $2 Arduino Nano form factor STM32 modules perhaps. They have SPI, actually they have USB even to squirt out the TS if fast enough.The STM32F103C8T6 might be able to do the job? I have a few somewhere. A lot cheaper than the FTDI module.

Mike
Last edited by g0mjw on Wed May 20, 2020 9:11 pm, edited 1 time in total.

YL3AKC
Posts: 41
Joined: Wed Aug 08, 2018 8:42 am

Re: Potential DATV settop box project (aka the Ryde project)

Post by YL3AKC » Wed May 20, 2020 9:06 pm

g8gtz wrote:
Wed May 20, 2020 8:51 pm
If height is an issue the flat nim version might be the best. There is an accurate mechanical drawing in the data sheet.
As Janis said in an earlier post the horizontal NIM are much more expensive and harder to source - besides BATC still has 100 of the vertical type so maybe best to avoid that if possible ;)

Noel
Get NIMs from Serit isn't big problem.
I purchased two horizontal NIMs from Serit.hk
Costs:
NIM - 25 USD
Shipping with DHL to YL - 45 USD (1.5 week delivery)
Local import taxes in YL - 19 EUR
So total: ~115 EUR
Each nim cost me ~55 EUR per unit
This is in quantity 2 unit.
I assume that for 100 units price will be lower and shipping costs will be more or less the same. Need to ask Serit friends.

As bonus: I got cofidential datsheets for NIMs. Interesting reading, but can't share them.

PS: I waited 2.5 months to respond to email and skype. :-D

Janis, YL3AKC

G4GUO
Posts: 665
Joined: Tue Feb 16, 2010 12:51 pm

Re: Potential DATV settop box project (aka the Ryde project)

Post by G4GUO » Thu May 21, 2020 7:52 am

A couple of points the DATV-Express team use Horizontal Serit NIMS so we can get them if needed.

The only issue is that Serit manufacture in batches so if you place your order at the wrong time
there can be quite a lead time on delivery.

The second point is the NIMs have serial as well as parallel modes. I would have to check
the datasheets from STMicro but I believe the parallel bus width can be changed as well (don't quote me on that).

- Charles

g0mjw
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Joined: Sat Sep 20, 2014 9:15 am

Re: Potential DATV settop box project (aka the Ryde project)

Post by g0mjw » Thu May 21, 2020 10:02 am

I wondered about the serial mode as the other NIMs have it, but without the detailed data sheet it's hard to tell as it is not mentioned. That would make it easier perhaps. I was thinking more about the STM32 overnight. Could this be a viable replacement for the FTDI board at a fraction of the cost? Putting some limited intelligence in the RX would make it much easier on the PC/PI.

Mike

YL3AKC
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Joined: Wed Aug 08, 2018 8:42 am

Re: Potential DATV settop box project (aka the Ryde project)

Post by YL3AKC » Thu May 21, 2020 12:02 pm

Just made quicklook on datasheet.
1) not possible to get 4 bit mode.
2) In serial mode data are sent via D7 pin
3) Serial clock source is NIM tuner, so, if it is possible, RPi must be in SPI slave mode. Need to read RPi datasheet for this mode. Usually RPi act as SPI master.
4) Need to study possibility to use parallel to SPI converter (FPGA, MCU, 74LVS597 etc) to convert parallel data in SPI. MCP23S17 have only 10 MBit serial bitrate. Usable for DATV 2MSym/sec, but useless if you want more. DSNG standard HD feed is 16.5 MBit or more.

Guys! Can we make these research in parallel?
I will go with parallel GPIO research.
Somebody go with serial/spi (RPI as slave) reading drom D7 pin.
Other guy go with parallel-to-serial+SPI converter (FPGA, MCU, 74LVS597 etc). RPI slave as master.
I am afraid that I don't have enough "horsepower" and time to research all 3 directions.

Another guy go with mechanical measurements/PCB desing. Need to place NIM on correct location. No need to connect NIM electricaly right now.

OK, neverwind. I'll try to make solder and experiments with parallel GPIO mode today.

Janis, YL3AKC
Last edited by YL3AKC on Thu May 21, 2020 12:30 pm, edited 1 time in total.

G4EWJ
Posts: 885
Joined: Wed Feb 17, 2010 10:11 am

Re: Potential DATV settop box project (aka the Ryde project)

Post by G4EWJ » Thu May 21, 2020 12:18 pm

MW0RUD: The 74HCT40105 would extend the latency limit to 16us, so could work. I'll try to set up the kernel module latency test on a running Portsdown.

G8GTZ: Definitely use both channels on the NIM. I'm sure Heather can advise. The second NIM is for 2 more channels.

G0MJW: I've had a look at the MCP23S17. I haven't figured out yet if it has buffering. The NIM is effectively a master device, so you have to be ready to accept what it gives.

YL3AKC: I got the chips confused there somehow. Can you tell which pins on the RPi are being used to interface to the TV Hat?

I think we should investigate NIM serial mode. If that works, then there's no need for any interface hardware. SPI slave mode on the RPi should be fine.

Brian
Last edited by G4EWJ on Fri May 22, 2020 3:06 pm, edited 1 time in total.

g0mjw
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Joined: Sat Sep 20, 2014 9:15 am

Re: Potential DATV settop box project (aka the Ryde project)

Post by g0mjw » Thu May 21, 2020 12:20 pm

I already have a Kicad PCB design so getting the NIM in the right place is not difficult. It more depends on what other components are needed and how it connects to the PI. It would make sense for the board to power the PI perhaps but I am not sure it would work as a hat as the PI needs active cooling and a board sitting on top would interfere with that. Perhaps a side by side approach and connection cable might be better. It would also minimise the height with the vertical NIM.

It would be good it someone could test the serial mode first. If it's possible it greatly simplifies the hardware.

Mike

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