Antti's LinuxTV Blog: October 2013

Teardown HD-901T2 DVB-T2


DVB-T/T2/C FM+DAB+SDR

That is relatively young device as it appeared to market around 2 months ago, beginning of September 2013. It is sold without any real brand, though model number HD-901T2 is mentioned by some sellers. USB interface advertises manufacturer string "astrometadvbt2" and product "dvbt2". From manufacturer string we could guess it is AstroMeta Co. - or not. Own USB ID, 15f4:0131, is assigned to that device by device vendor.

That DTV stick is basically almost same than RTL2832U + R820T reference design, but there is one big difference - external DVB-T/T2/C demodulator. It is also a little bit bizarre as it advertises unofficial SDR (provided by RTL2832P).

Looks like device is build upon some new Realtek reference design, whilst it may different somehow. Windows drivers are near Realtek drivers, but those are still customized (?) for that device. Drivers that are coming with the device, are in a quite bad shape as even standard BDA interface didn't work. Own Windows application is only application which could be used currently.

Initial Linux support is about to go in Kernel 3.13, or in a bad luck 3.14 as Kernel merge window is very near to open. Kernel driver has only DVB-T support at the moment, due to missing external DVB-T/T2/C demodulator driver.

Key components:
Realtek RTL2832P
Panasonic MN88472
Rafael Micro R828D

Hardware internals

RTL2832P, MN88472, R828D

All relevant components, RTL2832P, MN88472 and R828D, could be found from that side of PCB. Visible crystal near R828D is 16.000 MHz, clock source for R828D. Other side of PCB has 28.800 MHz crystal for RTL2832P and 20.500 MHz crystal for MN88472.

PCB printings:
FSC_USB_DVB-T2-C

Realtek RTL2832P

RTL2832P is same chip than RTL2832U, but it has extra TS (transport stream) interface to connect external demodulator. Shortly, RTL2832U is USB interface and DVB-T demodulator in one package. For more information about that chip see my old blog posts of RTL2832U.

Panasonic MN88472

MN88472 is DVB-T/T2/C demodulator. It is very first time when that chip is seen on PCTV device. Earlier DVB-T2 capable demodulators used for PCTV devices are Sony CXD2820 and Silicon Labs Si2168.

There is own 20.500 MHz crystal, which offers clock source for demodulator. TS bus (between RTL2832P and MN88472) is hardly visible. It is not clear whether it is connected using serial or parallel bus, though serial mode could be good guess, as there is no 8+ wires clearly visible needed for parallel mode.

I2C control bus is connected to RTL2832P I2C adapter.

Rafael Micro R828D

R828D is Low-IF hybrid silicon RF tuner. That tuner is very similar than R820T tuner used earlier for some RTL2832U devices. R828D is flagship model, whilst R820T is reduced to DTV terrestrial only reception. There is own 16.000 MHz crystal, which is a little bit odd as older RTL2832U + R820T designs used shared clock source from RTL2832U.

Tuner IF bus is connected to both MN88472 and RTL2832P. Control bus, I2C, is wired to RTL2832P I2C adapter only (RTL2832P I2C adapter is property of integrated RTL2832 demodulator).

PCB backside

Only chip visible is 24C08 8k serial eeprom. It contains USB configuration information, e.g. device USB ID and manufacturer strings. It is connected to RTL2832P via I2C.

Black 3-leg component is IR-receiver. It is connected also to RTL2832P, which offers RAW mode remote controller signals.

Crystal "Y2", 22.500 MHz, for MN88472.
Crystal "Y3", 28.800 MHz, for RTL2832P.

USB interface

IDLE current drain without a driver: 103 mA

lsusb -vvd 15f4:0131

Bus 002 Device 004: ID 15f4:0131 HanfTek 
Device Descriptor:
  bLength                18
  bDescriptorType         1
  bcdUSB               2.00
  bDeviceClass            0 (Defined at Interface level)
  bDeviceSubClass         0 
  bDeviceProtocol         0 
  bMaxPacketSize0        64
  idVendor           0x15f4 HanfTek
  idProduct          0x0131 
  bcdDevice            1.00
  iManufacturer           1 astrometadvbt2
  iProduct                2 dvbt2
  iSerial                 0 
  bNumConfigurations      1
  Configuration Descriptor:
    bLength                 9
    bDescriptorType         2
    wTotalLength           34
    bNumInterfaces          2
    bConfigurationValue     1
    iConfiguration          4 USB2.0-Bulk&Iso
    bmAttributes         0x80
      (Bus Powered)
    MaxPower              500mA
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        0
      bAlternateSetting       0
      bNumEndpoints           1
      bInterfaceClass       255 Vendor Specific Class
      bInterfaceSubClass    255 Vendor Specific Subclass
      bInterfaceProtocol    255 Vendor Specific Protocol
      iInterface              5 Bulk-In, Interface
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x81  EP 1 IN
        bmAttributes            2
          Transfer Type            Bulk
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0200  1x 512 bytes
        bInterval               0
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        1
      bAlternateSetting       0
      bNumEndpoints           0
      bInterfaceClass       255 Vendor Specific Class
      bInterfaceSubClass    255 Vendor Specific Subclass
      bInterfaceProtocol    255 Vendor Specific Protocol
      iInterface              5 Bulk-In, Interface
Device Qualifier (for other device speed):
  bLength                10
  bDescriptorType         6
  bcdUSB               2.00
  bDeviceClass            0 (Defined at Interface level)
  bDeviceSubClass         0 
  bDeviceProtocol         0 
  bMaxPacketSize0        64
  bNumConfigurations      2
Device Status:     0x0000
  (Bus Powered)