Page 1 of 1
Driver not seeming to find lead with CH340 serial interface
Posted: Thu Jul 29, 2021 5:41 pm
by g0bld
Hi
New to DMR here... I've just got a radio that's running OpenRD5R (May 18 2021). I've got a programming lead (a "multi" lead that has a CH340 in it) and downloaded the latest version of CPS (2021.06.10.01)
When I install it, it asks if I want to install the drivers, and it opens a DOS window that extracts the drivers then says it installs them...
BUT CPS can't see the radio, and no drivers are associated with the device. When I try to read the code plug I get "Device not found" - I presume because there's no OPENGD77 COM port available.
(In Device manager, the port is still showing as "unknown" without a driver linked)
I've also tried installing CPS with the drivers that came with the lead already installed (it shows up as COM3- so I assume its found the interface), but it still doesn't set up... is the OPENGD77 driver a "virtual" COM driver, or does it expect a specific type of interface chip?
I note that you don't seem to be able to download the OpenCD77 driver separately any more to look at what it is doing...
Any clues as to what I'm doing wrong welcome!
TIA Neil
Re: Driver not seeming to find lead with CH340 serial interface
Posted: Thu Jul 29, 2021 10:45 pm
by VK3KYY
g0bld wrote: ↑Thu Jul 29, 2021 5:41 pm
Hi
New to DMR here... I've just got a radio that's running OpenRD5R (May 18 2021). I've got a programming lead (a "multi" lead that has a CH340 in it) and downloaded the latest version of CPS (2021.06.10.01)
When I install it, it asks if I want to install the drivers, and it opens a DOS window that extracts the drivers then says it installs them...
BUT CPS can't see the radio, and no drivers are associated with the device. When I try to read the code plug I get "Device not found" - I presume because there's no OPENGD77 COM port available.
(In Device manager, the port is still showing as "unknown" without a driver linked)
I've also tried installing CPS with the drivers that came with the lead already installed (it shows up as COM3- so I assume its found the interface), but it still doesn't set up... is the OPENGD77 driver a "virtual" COM driver, or does it expect a specific type of interface chip?
I note that you don't seem to be able to download the OpenCD77 driver separately any more to look at what it is doing...
Any clues as to what I'm doing wrong welcome!
TIA Neil
You have to use the specific cable for that radio.
It is not a CH340 type.
AFIK. The Baofeng DM-1801 cable works on the RD5R, but the GD-77 cable does not
You can make a GD-77 or MD-380 cable work on the RD-5R, but you would need to take it apart and swap USB D+ and USB D-
Re: Driver not seeming to find lead with CH340 serial interface
Posted: Thu Jul 29, 2021 11:22 pm
by G4EML
As Roger says, these DMR radios do not have a chip in the cable. The cables are just wires. The serial port is created by the processor in the radio and not by a separate chip.
Colin.
Re: Driver not seeming to find lead with CH340 serial interface
Posted: Fri Jul 30, 2021 11:26 am
by VK3KYY
Just to elabourate on what Colin has writen
Most modern processor chips, including the ones in these radios, have built in USB, which is what the cable connect to.
Re: Driver not seeming to find lead with CH340 serial interface
Posted: Sun Aug 08, 2021 3:39 pm
by g0bld
Thanks for the replies.... That makes sense.
But now the follow-up question
(I have looked and any hardware description seems to be very thin on the ground for these beasties...)
Which of the "accessory" plug(s)' Tip/Ring/Sleeve connections are used Ground, D+ and D- (I'm assuming it doesn't need +5V!) on an RD-5R type radio (its actually a DM-9HX, which is the variant with a large battery as far as I can tell!). I've got a speaker/mic so have all 6 connections available easily to make it up as a temporary lead....
TIA
Neil
Re: Driver not seeming to find lead with CH340 serial interface
Posted: Sun Aug 08, 2021 8:40 pm
by oh1fss
You can find the programming cable diagram for RD-5R here:
https://radioamateur.us/opendm5r/
The cable for RD-5R is the same as GD-77
except that D+ and D- are swapped.
Re: Driver not seeming to find lead with CH340 serial interface
Posted: Mon Aug 09, 2021 8:50 am
by g0bld
Brilliant. Thank you.
Think there's scope for a stereo 3.5mm socket on the speaker/mic that disconnects the "normal" connections to the plugs and connects to the USB lead - the plug will need the 100Ohm resistors inside the plug...
Neil.
Re: Driver not seeming to find lead with CH340 serial interface
Posted: Mon Aug 09, 2021 9:21 am
by oh1fss
The site says that "Two resistors can be omitted". I built my cable without the resistors. I used 2.5 mm and 3.5 mm stereo plugs and a USB connector.
73, OH1FSS