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Serial port?

Discussion in 'HD/HDR-FOX T2 Customised Firmware' started by matbl, Nov 14, 2011.

  1. matbl

    matbl Member

    I know this is the customised firmware section but it seems that this is where most of the hacking stuff goes on. Please move the thread if it is misplaced.

    I saw a few references to a serial port inside the HD-FOX T2. Did anyone try it?
    Is there one inside the HDR as well?
     
  2. af123

    af123 Administrator Staff Member

    I haven't opened mine up but from what I've seen posted on here there is no visible serial port. The Linux OS sees one and there's even a dormant configuration section for running a getty on it in the inittab, it also seems to be streaming debug/diagnostic output from micom .
    It is likely to just be a pin pad used for internal testing.
     
  3. matbl

    matbl Member

    I was thinking more of getting the startup info from the cfe bootloader and similar stuff.
    A pin pad is fine, I just wanted to know if anyone tried it and if there actually was any output at all on it before I bring out the soldering iron... ;)
    If someone tried it, a pin-out would be help full as well...
    Or is there maybe an accessible jtag... ;)
     
  4. xyz321

    xyz321 Well-Known Member

    I did have a quick look inside. Whilst there a few places on the PCB where connectors have not been fitted I couldn't see any obvious markings for a UART.

    I did wonder whether any of this might be available on the CAM slot (I don't have any info. on the CAM connections).

    PS. You might not see much output from the kernel since it has been compiled without printk support.
     
  5. matbl

    matbl Member

    xyz321: Ok thanks.

    It's not the kernel output I'm interested in. It's the bootloader output...
    And I have a different software as well since I'm in sweden... Our model is called BXR-HD+ but it is more or less a HDR-FOX T2, main chip is the same and the pcb is almost the same (no 1080p upscaling and smart card reader instead of CI-slot).

    And no, such signals isn't available on the CI-slot (CAM-slot) as far as I know.
     
  6. matbl

    matbl Member

    For anyone interested, there is a serial port with output in my BXR-HD+ which probably means there is one in the HDR-FOX T2 as well. I got some help doing some measurements with an oscilloscope today. :)

    Don't know what you would use the one in the hdr-fox for since it's wide open anyway...
     
  7. xyz321

    xyz321 Well-Known Member

    To help debug a problem with running a custom kernel.
     
  8. matbl

    matbl Member

    Of course.
    I'll let you know after I have had the time to solder on the pin headers. Tomorrow evening maybe...
     
  9. matbl

    matbl Member

    Bah!
    Soldering was too advanced for me. Small holes and small solderingen pads...
    Well. the box still works anyway...
     
  10. Black Hole

    Black Hole Ron Glum

    I expect surface-mount techniques are required, even then the solder mask layer might make it difficult if just enough pad land is left for test probes to make contact.
     
  11. matbl

    matbl Member

    No. These were clearly for hole mounting of pin headers. I know my way around pcb and hw design enough to know a hole from a surface mount pad...
     
  12. Black Hole

    Black Hole Ron Glum

    Fair enough. Some pads have vias near them, which really are small!
     
  13. matbl

    matbl Member

    I've found some stuff in the cfe bootloader but need someone with a hd-fox or hdr-fox to verify it for me (it doesn't work with my bxr-hd+ version).
    Is there anyone that has a serial to usb cable, a null modem cable, a computer with a serial port (or a second usb to serial cable) and a hd or hdr box and is willing to do the following simple test, I'd be thankful.

    I will not ask you to send any data to the box, just listen for data from it.

    Connect the serial to usb cable to one of the humax usb ports and the other end of it to the null modem cable and the other end of that to the computer's serial port.
    Start a serial program like tera term (google/wikipedia) and log the output as binary data. Serial port should probably be at 115200, 8, n, 1, but I'm not entirely sure about the speed.
    Reboot the humax and see if you get any data, you must let it go through the loading screen so a power switch reboot or something like that. If you don't get anything, try the other usb port on the humax and/or other speeds.
    If I'm correct you will get exactly one byte of data with the value 0x02 so it's not sure it will print on screen.

    Anyone?
     
  14. af123

    af123 Administrator Staff Member

  15. matbl

    matbl Member

    You don't need a computer with a serial port. Use the following setup: HUMAX_USB<->Serial<->null modem cable<->Serial<->COMPUTER_USB.
    Two serial to usb cables with a null modem cable between the two male rs-232 serial connectors.
    I'm using that setup here but don't get much out of my box. And yes, I've verified the serial stuff between two computers.

    No, I hadn't seen that earlier. Seems like ttyS2 is the remote input then... Which makes me wonder what the three pin header places on the board are, they can't all be serial ports... Hmm...
     
  16. af123

    af123 Administrator Staff Member

    Then I need two USB->Serial cables.. I should be able to borrow an extra one.
     
  17. MartinLiddle

    MartinLiddle Super Moderator Staff Member

    As you may be aware, 0x02 is the initial byte sent by the earlier Humax PVRs to initiate the firmware update process via a serial port.
     
  18. matbl

    matbl Member

    No I wasn't. I never owned a Humax before. Thanks!
    Are you aware of any text anywhere describing the protocol for that?

    BTW, if I understand the bootloader correctly, you can also get it to send the flash contents to you which is what I'm interested in...
     
  19. MartinLiddle

    MartinLiddle Super Moderator Staff Member

    Sorry no. When I wrote flash9200 I figured it out by looking at dumps from a serial port monitor. Try sending back a 0x06 and see if it returns a 0x40.
     
  20. matbl

    matbl Member

    I would happily send 0x06 if I could get my humax (swedish version of HDR called BXR-HD+) to actually send 0x02 on any port.
    Or does it require some kind of input first?

    Tonight, I have investigated all three possible internal uart connections (4 holes each to clearly hold pin headers) but none of them writes any serial data. And yes, I used a voltage level converter to convert the cmos-levels to proper rs232 levels.
    I know at least the middle one sends some kinds of pulses so my next guess is USB which fits nicely with the pinout of +5V, 3.3V signalling on 2 pins and gnd on the fourth. But getting a reliable USB signal from four soldering pads is kind of hard...