Enable USB on DM500hd by Dream Elite Team
Here is the guide to activate Usb controller on your DM500hd with a little hw modification.
Warning: Removing resistors means you are going to VOID WARRANTY and everything happening since then will be at YOUR OWN RISK, no one will take responsibility for your own actions.
Warning:This guide is Dream Elite team exclusive. Nobody have the persmission to redistribute the guide and the content in any way or form
About cable connector.
You can use a normal Usb cable (as for example from old Pc)
Remember only to open the way for the pin N. 10.
USB HUB with Overload Protection
For your info
E-tech now new name Eminent
have USB 4 ports HUBs with GL850 chip ( Overload Protection ).
It is not difficult to find and not expensive.
I found one at home
E-tech USB-hub 4-poorts (4 x USB 2.0)
with google.com you can serach this model USHB02
I have open USB hub and it is all in very good
can be power supplied from USB or Exten Max 2.5A
Look like most USB hubs from E-tech,new name Eminent
using this GL850 chip and inside i have see good protection.
Of course you can use other models
but with this chip
everything will be at YOUR OWN RISK.
This is only info.
Some notes about the 500hd usb crap and relative dirty hack.
In 500hd the usb 5v are taken directly from the main 5v power regulator output, if you make a short on the main 5v line, the regulator can be fried and it could output directly 12v instead of 5v, flaming brcm and tuner.
In 800hd for example the usb 5v is supplied by a max1823, a power switch which tells back the brcm about current status.
INA/B are input voltage, while OUTA/B the output voltage that goes to the usb connector.
FAULTA/B are signals back to the broadcom (pulled high).
ONA/B are used to remotely force the ON/OFF power to the OUTA/B, in dm800 seems not used, in fact we see a CONFIG_USB_BRCM_PWR_CTL not set into kernel config, so the max1823 is in fixed ON condition, unless an overcurrent occurs.
When an over-current event occurs, the max1823 automatically cuts off power to OUTA/B and drives FAULTA/B to GND, so the broadcom knows an overcurrent event occurred an disables the whole usb controller.
In 500hd, max1823 is missing and lines which should come from FAULTA/B are forced to gnd with R1010/11, resulting in a permanent over-current state.
brcm-ehci brcm-ehci.0: USB 0.0 initialized, EHCI 1.00, driver 10 Dec 2004
usb usb1: Product: BRCM EHCI
usb usb1: Manufacturer: Linux 2.6.12-5.1-brcmstb-dm500hd ehci_hcd
usb usb1: SerialNumber: ehci-brcm
hub 1-0:1.0: USB hub found
hub 1-0:1.0: 2 ports detected
10 Dec 2004 USB 2.0 'Enhanced' Host Controller (EHCI) Driver (EHCI-brcm-1)
hub 1-0:1.0: over-current change on port 1
You can see ehci controller messages and hub messages (overcurrent event btw), that's because the integrated broadcom usb controller has also an integrated hub (i think like all usb controllers out here, but i could be wrong).
Looking at usb2.0 specification and hub.c sources, it's the hub itself that has the responsibility of monitoring and cuting off vcc in case of overcurrent events, so.....connecting an esternal hub with overcurrent protection (and external powered) should be enought to be 100% safe.
I've took a look at crap chinese usb hub today, it has not any overcurrent protection, but i saw on ebay some hubs having it, specially the ones with Genesys GL850 chip.
No one can guarantee to you that in case of USB stick failure
will cause a malfunction/defect Box.
Therefore it is desirable to have at least minimal protection
such as protection against short circuit ( plus the voltage
Protekcion can be done with special PTC resistor fuse
in this case could be used with the USB stick inside Box
but with special measures against short-circuiting.
Another problem could be heat inside box.
The idea of the USB hub I feel more confident.
Of course it is even possible install a USB hub in the Box.
This USB HUB I have is protected with special chip
I wrote in the last post.
It costs only about +- 15 euros.
I have test this USB Hub and is working very good no problems
after 2 days testing.
Of course all this is on your personal risk.
For electronic experts simple protection .
My picture but i prefer USB HUB cheap easy and good
tested USB stik without protection
and of course it works
but in this case the box is in danger.
I think you need to have a minimum protection plus line ( red wire)
say a quick fuse
, or even better Special PTC fuse for USB protection.
In this way you could use a USB stick but not the HDD .
All of this is your personal risk.
You can use the USB stick directly connected
but in the case of short circuit or voltage transitions on the data lines
it wil came to defect DM500HD.
Therefore is advisable to use a good USB HUB
that will protect DM500HD lines not only + 5 V
but also data lines.