Build your own USB tuner

MiniTiouner schematic

Messagede F6DZP » Mer 29 Juin 2016 13:57

My first draft:
schéma crayon Minitiouner sans alim.jpg
schéma crayon Minitiouner sans alim.jpg (140.75 Kio) Vu 1913 fois

easier to read:
Schema Minitiouner Sharp_.jpg
Schema Minitiouner Sharp_.jpg (106.15 Kio) Vu 1914 fois

As can be seen from the schematic there are only a few components in the MiniTiouner USB tuner

Operation of the hardware is very simple:
- MiniTiouner sends the commands using I2C to set the Zero Tuner (Frequency) and demodulator (Symbol Rate).
- The hardware returns the locking status, RF level, MER, constellations...
- When TS is ready to be extracted (TS status OK known via I2C), we get the availability of Bytes on the parallel Bus by observing the Clock, DataValid and Error signals.

montage avec NIM samsung_txt.jpg
montage avec NIM samsung_txt.jpg (139.91 Kio) Vu 1911 fois

NIM tuner (Network Interface Module)
the NIM tuner is a compact module which takes in the L band RF signal and produces transport stream data out.

DNBU10711IST_a plat avec infos_.jpg
DNBU10711IST_a plat avec infos_.jpg (92.62 Kio) Vu 1911 fois

BS2F7VZ0169_.jpg (94.34 Kio) Vu 1911 fois

NIM open info_.jpg
NIM open info_.jpg (83.87 Kio) Vu 1911 fois

Which NIM to use?
The target is to be able to lock on low SR down to SR120 kS/s and lock quickly when QSB is a problem. In order to do, this we need the same demodulator chip (STV0903 or STV0913) as the S2-1600 so we can obtain the same performance.

Eventually I selected the Sharp BS2F7VZ0169, Eardatek EDS-4B47FF2B+ and Samsung DNBU10711IST units and bought a small number of each from Ebay / AliExpress and started to build my own USB tuner card. However, it was more difficult when we wanted to buy large quantities of units but eventually many units of the Eardatek or Sharp units were sourced by BATC and are available in the BATC shop.

It is very difficult to find documentation about what kind of chip is used inside a NIM and the only documentation I have found was for the Sharp BS2F7HZ0169. For the 2 other models, I had to examine other USB Tuner cards (Prof 7500) or Set Top Boxes to find what is each pin for.

NIM pinouts : the basic functions are as follows:
Pins 1-3: LNB voltage/22 kHz input and power supply for the transistor booster.
Pins 4-5: Power supply for the Zero Tuner
Pins 7-9: I2C
Pins 10 & 12: Diseqc/22kHz input and output
Pins 11 & 13: Power supply for the demodulator
Pins 14-21: D0-D7 Parallel Data Bus = Transport Stream Data out
Pins 22, 23 and 25: signal to know when data are available on the bus
Pin 24: Strobe/Sync = signal that say when we have the SYNC byte of a TS packet
Pin 26: Reset of Demodulator

USB interface choice
I started using two different USB interfaces, the Cypress CY7C68013 and the FTDI FT2232H which is the same model used by the Digilite project and stocked in the BATC shop. After a week of fighting against the documentation, drivers and DLL, the bad chip on Chinese Cypress module where the chip’s name is sometimes changed, I decided to keep only the FT2232H mini module to finish the first version of MiniTiouner.

FT2232H config.jpg
FT2232H config.jpg (83.99 Kio) Vu 1911 fois

..... to be finished

Jean-Pierre F6DZP
Messages: 537
Inscription: 24 Déc 2010

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