Using the Tektronix TDS Console Port - Page 1
Forum section: electronics / repair

author: mwbarth36
author_rank: Regular Contributor
timestamp: July 09, 2022, 06:55:15 pm
content: Please can someone help! I have been trying to use the Console Port of a Tektronix TDS540 scope for troubleshooting. I understand that it should provide a printout of the status with error messages at powerup if connected to a Terminal program of a computer. Here is what I have.......... I have purchased a conversion board allowing the Console Port to plug into the RS-232 connector normally used by the scope, thus, using the on board RS-232 circuit of the scope. I then have an RS-232 to USB conversion Cable/Adaptor using the normal USB/RS232 conversion chip set. I am then running the Terminal program provided by Windows 10 to monitor the Port.When I run the Terminal program and power on the scope, it runs the normal start up tests, but nothing is printed on the computer. I have no idea as to the settings required for compatibility with the RS-232 output of the scope or how to set the baud rate of the Terminal program to match that of the scope. Can someone help, Please?I feel there must be, somewhere, a list of commands to request data from the scope or even read the memory, etc. Does anyone know if such information is available? Any information which might help will greatly appreciated!

author: Andy Watson
author_rank: Super Contributor
timestamp: July 09, 2022, 08:01:24 pm
content: See this forum thread:https://forum.tek.com/viewtopic.php?t=137307It's claimed that the baud rate is 9600: "The console port uses 9600 Baud, 8N1 with RTS/CTS flow control." You will have to find out how to configure your USB/Serial adaptor to 9600 before you can talk to the scope.I would temporarily forget about the scope and concentrate on configuring the USB adaptor - create a loop-back connection and get that working as your first stepping stone.

author: mwbarth36
author_rank: Regular Contributor
timestamp: July 10, 2022, 05:09:34 pm
content: Thank you for your reply. Here is where I am at this point. I did find out how to configure the Terminal program and have it configured as you and others say the Console Port is configured. 9600 baud, etc. That did not appear to help. It does make sense that the RS-232 to Usb would need to be set to a configuration, I see no way to do that, will have to investigate further. (I am an 80+ year old electrical engineer who started with computers using a DEC PDP 8i) Wish I could go back to the days when all computers had a RS-232 port! I tried to open the link you gave, but it will not open, maybe too old. I see that a lot with links from that site.Thanks again for the advice! Will keep trying.

author: Stray Electron
author_rank: Super Contributor
timestamp: July 10, 2022, 06:52:15 pm
content: This might have already occurred to you, especially to an old timer like you, but does your cable and your terminal support RTS/CTS? Those are hardware signals and the two necessary wires have to be in the cable. A lot of the new-ish RS-232 ports and cables didn't include those signals and basically ran asynchronously.I still keep an HP RS-232 Protocall Analyzer around for the purpose of diagnosing unknown baud rates, hand shaking, etc. Also like you, I wish that they had stuck with RS-232 for basic troubleshooting and basic operation of equipment.

author: Andy Watson
author_rank: Super Contributor
timestamp: July 11, 2022, 12:36:26 am
content: I suspect that you have to give the appropriate handshake signals to the TDS to allow it to send information.My first encounter with a "real" computer was a PDP8. Alas, at the time I was so far down the corporate food chain that I wasn't allowed to touch itIn my next job we had a PDP11 that ran, ... everything! It ran stock control and salaries but its mainstay was providing a development platform for the Texas 9900 (in assembler of course) - and all on a pair of 10M byte hard drives. Its resources were distributed throughout the company on RS232. The company produced electronic hardware (to customer specification), much of which involved using RS232. Despite being well specified, RS232 was the bane of our lives. It seems that no two manufacturers could agree on how they interpreted the RS232 "standard". We had a kind-a mantra, "link 4 and 5, and 6 8 and twenty" to get a serial link working. Those pin numbers refer to the 25-pin D sockets, your mileage may vary for the 9-pin variety.I believe that pins 4 and 5 were the RTS and CTS signals. Whilst short-circuiting the handshake protocol is less than ideal, it usually caused the serial link to function sufficiently to enable further debugging.Ah, happy times(Not)

author: mwbarth36
author_rank: Regular Contributor
timestamp: July 11, 2022, 02:53:49 pm
content: There were not many instructions with the cable. Will check to see if RTS/CTS is supported. Thanks for the Reply!

author: mwbarth36
author_rank: Regular Contributor
timestamp: July 11, 2022, 03:37:24 pm
content: Been 'There', Done 'That'. First memory system I remember was 16 Kbytes of Core supported by a DEC Tape. That was State of the Art in 1972. Interesting to hear about your experience with RS232, mine was pretty much the same, not well defined Standards (only 485 was worse).Here is where I am with the problem. Yes, one has to configure the UART in the Cable. The cable I have is from Cablecreation using a PL-2303 chip set. No instructions were included. Going to the Cablecreation Web site is of little help, almost nothing works. They say to set up the PL-2303 chip set all one has to do is to plug the cable into a USB port if using Windows 10, and the 'Wizard' will guide you through the set up. Yeah, Right! Plugging the cable into a known working usb port of a Dell computer operating Windows 10 gets absolutely no response, it is not detected. I asked for support on the Cablecreation Web site and less than reassuring. There is no way to load the Drivers for Windows 10 other than using the 'Wizard' which does not come up when the cable is plugged in.What I decided to do was to send the Cablecreation cable back and order one that uses the FTDI chipset. They appear to have a much more user friendly Web site, and a method for downloading the correct Drivers. Also, RTS/CTS is definitely supported.I will pick the Thread up again in a few days when I receive the new cable.Thanks everyone for your replies, they are appreciated!

author: shakalnokturn
author_rank: Super Contributor
timestamp: July 13, 2022, 10:54:22 pm
content: You took the right direction!I have either a Maxim or FTDI with translucent plastic housing. Added-in SMT LEDs on RX and TX lines to gain time in getting serial links working.

author: mwbarth36
author_rank: Regular Contributor
timestamp: July 14, 2022, 10:03:26 pm
content: The continuing battle to get data from a TDS540. I have the adaptor cable plugging the Console port into the Option 13 connector, the RS232 connector of Option 13 connected to a Gearmo USB to RS232 conversion cable (this cable has a plastic part with LED's showing activity on all lines), the USB end of this cable going to a usb port on a computer running Windows Terminal. I power on the computer, then the scope. The scope goes through it's start up tests, which all PASS. No print out happens! I would believe that it is a problem with my setup, but I see no indication from the LED's that the TDS540 is ever transmitting anything. The only LED that is on is the CTS, and it is on all the time. No LED action on the data lines or any other line. I tried both a straight thru connection and a null modem connection, NOTHING!Any suggestions where I am messing up?? Not really clear on how to set the Com Port up with the gearmo cable, it has the FTDI chip, but the instructions do not make any sense.Any help will be appreciated!!

author: shakalnokturn
author_rank: Super Contributor
timestamp: July 15, 2022, 10:30:45 pm
content: Have you been able to check your new USB to RS232 adapter with a loopback?Tried scoping TDS Tx line during boot to see if it actually outputs at all?Edit: A commonly reported mistake is connecting to the CPU PCB's edge connector upside-down.

author: inse
author_rank: Super Contributor
timestamp: July 16, 2022, 12:52:18 pm
content: Did you verify with a different scope that the DUT is providing any data at the RS232 at all?

author: mwbarth36
author_rank: Regular Contributor
timestamp: July 16, 2022, 04:06:38 pm
content: My next task is to check each separately. Looking at the output of the RS232 when the scope is booting, what lines do I need to tie together to satisfy the flow control? Once I establish data is being sent, I will check the USB to RS232 with loopback.

author: inse
author_rank: Super Contributor
timestamp: July 16, 2022, 05:27:37 pm
content: Without specific knowledge of the Tek implementation, the debug consoles I know just shove out the data without respect whether anyone is listening or not.If any handshake is necessary, I would connect RTS to CTS.Seehttps://en.wikipedia.org/wiki/Null_modem

author: mwbarth36
author_rank: Regular Contributor
timestamp: July 16, 2022, 08:40:58 pm
content: Thanks again, everyone for suggestions! I have made some progress as follows. I first looked at the output pin of the RS232 connector on the Option 13 module with a scope. When I turned the scope on there was an attempt to send data, however the RS232 levels were - 2 Volts and +4 Volts...........not good. Then I remembered this module was from a TDS540 and the caps had not been changed. I changed the capacitors and tried again. Sure enough, the output was there and the levels were good. Next I re-connected the Gearmo cable with the LED's on all signal lines to the computer using a 'straight through' connection. I restarted first the computer, then the scope. No sign of life, no lights were on. I then used a Null Modem connection, and restarted the test. When the scope powered first the CTS light came on, next the DSR light came on, and finally the Rxd light indicated that data was being received. However no data was printed on the computer screen. I am using Windows Terminal.I suspect that I do not have the Gearmo cable configured correctly. I followed the on-line instructions for setting up the cable. I did set all of the RS232 parameters to that quoted for Option, but not sure I understand how to set the Com port. Seems to me I need to I need to set a Com Port in both the Gearmo and in the Terminal program. I can set the Gearmo to any number of Com Port's, but how does Terminal know which one I have assigned?Guess I need some more help.

author: shakalnokturn
author_rank: Super Contributor
timestamp: July 16, 2022, 11:37:40 pm
content: I'll usually avoid any un-needed software in Windows, install only necessary virtual com FTDI drivers.Check COM port number for FTDI device in control panel. I don't usually play with the configuration there, just leave the speed at maximum supported by hardware.Use a decent terminal program (my favourite is Realterm) that allows you to choose the right com port easily. (At this point I'll usually do a minimum Tx-Rx loopback to be sure the software and hardware are working together.)

author: inse
author_rank: Super Contributor
timestamp: July 17, 2022, 04:26:28 am
content: Btw the link rom reply #1 worked, after 'checking my browser' for three times, I was granted access.Interesting stuff, may be helpful for your repair - good luck!

author: mwbarth36
author_rank: Regular Contributor
timestamp: July 18, 2022, 01:53:26 am
content: I see nothing under Control Panel that would indicate what Com Port is used by FTDI devices. In device manager, under Ports is listed Communications Port (COM 1), and Intel(R) Active Management Technology - SOL (COM3). Have no ideal as to what the latter is, so maybe COM1? I believe I will try using the Terminal program you suggest (Realterm).

author: shakalnokturn
author_rank: Super Contributor
timestamp: July 18, 2022, 02:01:03 pm
content: I believe that in "device manager" it should at least give some information on being an USB device if not fully identified as FTDI. I suspect that COM1 may be on your computer's motherboard, although no one uses brackets to bring them out any more sometimes the RS232 header is there. Looking at driver details should give you clues.Did you download the FTDI VCP driver?With device manager open, try plugging the FTDI device into USB see if anything new pops-up in the list.If there's absolutely no sign of it check USB port is working.This may also help:https://learn.sparkfun.com/tutorials/how-to-install-ftdi-drivers/windows---quick-and-easyhttps://learn.sparkfun.com/tutorials/how-to-install-ftdi-drivers/windows---in-depth

author: mwbarth36
author_rank: Regular Contributor
timestamp: July 19, 2022, 06:44:13 pm
content: Some progress............I guess.........I opened the Device Manager and under Ports it only listed ECP Printer Port (LPT1). Next I plugged in the USB end of the Gearmo cable, and USB Serial Port (COM 1) was added. So, I believe I am connected to the computer correctly and the usb Port is working. Further more, if I click on the port I get on screen the Manufacturer as FTDI, and the message 'The device is working properly'. I look at the Port settings and they are set to 9600 baud, 8 data bits, one stop bit, no Parity, and no flow control. These are the quoted settings for the TDS Console port. Everything seems to be in order. However when I connect the cable to the Option 13 serial port through a null modem connection, and turn on the scope, the CTS/RTS lights first come on and as the scope goes through it's startup sequence the TXD and RXD lights flash as if they are sending bursts of data. Nothing appears on the Terminal program of the computer. It is very difficult to get anywhere with Gearmo, I have no idea where to go from here. Hope someone can help! Please!

author: inse
author_rank: Super Contributor
timestamp: July 19, 2022, 08:31:41 pm
content: I am puzzeled why both TxD and RxD lights flash, your computer should only listen so far.Is the debug console a full implemented RS232 or only the TTL interface?"I have purchased a conversion board allowing the Console Port to plug into the RS-232 connector normally used by the scope, thus, using the on board RS-232 circuit of the scope."I don't know whats going on here...can we see some photos, please?

author: mwbarth36
author_rank: Regular Contributor
timestamp: July 19, 2022, 09:02:30 pm
content: I just checked the Gearmo cable with a loopback test. There is no LED activity at the RS232 end of the cable. That can't be correct, can it? When I am plugged into the scope's Option 13 DB9 the CTS comes on, then the DSR comes on, then the RXD is active, so the scope is the only end getting signals to the Gearmo cable. Next step I will try another Terminal Program to see if that helps. Am I on the right track??

author: mwbarth36
author_rank: Regular Contributor
timestamp: July 19, 2022, 09:06:54 pm
content: My error, only the RXD lights flash. One has to be looking straight on or the light bleeds to the next position. The TXD light does not blink, it stays 'off'.

author: mwbarth36
author_rank: Regular Contributor
timestamp: July 19, 2022, 09:11:17 pm
content: I am using Option 13 also, it is full RS232. I, too, purchased a that board.

author: Sceptre
author_rank: Regular Contributor
timestamp: July 20, 2022, 04:21:00 am
content: I suspect that your terminal program isn't set up correctly. If the TXD indicator doesn't blink when pressing keys on the PC keyboard, that's a hint that the settings are amiss. If you're still using Realterm, seehttps://realterm.sourceforge.io/. The port settings should be in the lower right corner of the window; the Baud Rates & Ports section of the web page shows the Port dialog tab.Good Luck!

author: mwbarth36
author_rank: Regular Contributor
timestamp: July 21, 2022, 01:54:30 am
content: I now have the Terminal program, Realterm, controlling the led's on the Gearmo cable. I have the RS232 end in a 'Loopback' configuration. While I do see the Txd and Rxd leds blink everytime I hit a key on the keyboard, something does not seem right. I only get the character I select once on the screen, I would expect to get two characters printed, one from hitting the key, and one from receiving the loopback character. I have not connected it to the scope yet (a task for tomorrow), but I am betting I will not get the data from the scope printed to the screen. Realterm has a couple of dozen set up parameters that I have no idea as to there purpose, it may be that something is still not set up properly. Does anyone have any suggestions???

author: horo
author_rank: Regular Contributor
timestamp: July 21, 2022, 07:20:32 am
content: Typical a terminal works like this: Hit a key -> send it to TxD; Receive data from RxD -> display it on the screen.You can check it by cutting the TxD- RxD loopback connection -> I would expect no more characters on screen.

author: inse
author_rank: Super Contributor
timestamp: July 21, 2022, 12:43:05 pm
content: And usually you can configure the terminal program to echo the keys to the screen.

author: mwbarth36
author_rank: Regular Contributor
timestamp: July 22, 2022, 07:05:37 pm
content: I finally was able to get Realterm connected to the TDS Console Port and get the printout during start up. Mostly the problem was just getting Realterm configured correctly, it is not a 'straight forward' task!I want to thank everyone for their advice, every bit helped! I would not have been able to figure it all out without the help. Thanks again!

author: Fuma
author_rank: Newbie
timestamp: July 03, 2023, 07:46:56 pm
content: Hello, I wanted to know if the RS232 port is required to see the tests on a terminal during the boot of TDS540 or the GPIB port is enoughIs it necessary to make settings on DIP Switch Options to view the tests on the terminal?Thanks.