Re: [Elecraft] K2 - KIO2 stop bit oddity
The receiver's stop-bit setting needs to be greater than or equal to the stop bit setting of the transmitter. It is OK for the transmitter to You meant less than, not greater than, although, as you noted later, receivers generally don't have a stop bits setting. Yes. send two stop bits and for the receiver to be set for one stop bit. It won't hurt a thing. Most UARTs use the stop bit setting to affect only the transmitter (RS-232 sending part of the device). The receiver will Delete RS232. (In fact, historically, current loop was used for the physical interface.) True, once the mechanical teleprinters fell from grace, current loop fell by the wayside. (Unless you were connecting to DEC hardware. I have implemented more than one 20mA current loop to RS-232 converter in my life.) handle anything that is at least one bit-time long for a stop bit. Modern UARTs accept stop bits that are just over half a signalling unit in length (they sample in the nominal middle, but there is a limited sampling clock resolution. They need to accept ones that are strictly shorter than the transmitted ones, because, as we are talking about asynchronous signalling, they need to be able to cope with recovering from false start bits and cope with clock rate differences (more common on mechanical devices, but some electronic devices rely on these to allow working with convenient crystals. (When sending asynchronous data over 1200 bps synchronous modems, sometimes no stop bits could be sent over the wire, if the source clock was fast, as, being synchronous, there was no option to shorten the stop bit. Stop bits were re-inserted before creating the baseband output; I believe they ran the output clock fast to ensure that this worked.) You are, of course, correct. I should make sure that I am rigidly correct when I write and I was being sloppy. Having implemented UARTs in both software and hardware, and then the protocols to run over them (I am one of the authors of PPP and the architect for MLPPP) I do have a modicum of understanding. Longer stop bits just reduce the maximum rate (characters per second) that you can send data. And give better recovery from false start bits - not a problem you should have on a short piece of wire. Incidentally, 4800 baud is normally sent with one stop bit. As noted elsewhere, it is only really for mechanical devices that one needed longer ones, so it tends to be 110 and below (maybe 300) that uses 2, or for, 5 unit, Baudot, 1.5. -- David Woolley The Elecraft list is a forum for the discussion of topics related to Elecraft products and more general topics related ham radio List Guidelines http://www.elecraft.com/elecraft_list_guidelines.htm ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com -- 73 de Brian, WB6RQN Brian Lloyd - brian HYPHEN wb6rqn AT lloyd DOT com ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
Re: [Elecraft] K2 - KIO2 stop bit oddity
Brian Lloyd wrote: The receiver's stop-bit setting needs to be greater than or equal to the stop bit setting of the transmitter. It is OK for the transmitter to You meant less than, not greater than, although, as you noted later, receivers generally don't have a stop bits setting. send two stop bits and for the receiver to be set for one stop bit. It won't hurt a thing. Most UARTs use the stop bit setting to affect only the transmitter (RS-232 sending part of the device). The receiver will Delete RS232. (In fact, historically, current loop was used for the physical interface.) handle anything that is at least one bit-time long for a stop bit. Modern UARTs accept stop bits that are just over half a signalling unit in length (they sample in the nominal middle, but there is a limited sampling clock resolution. They need to accept ones that are strictly shorter than the transmitted ones, because, as we are talking about asynchronous signalling, they need to be able to cope with recovering from false start bits and cope with clock rate differences (more common on mechanical devices, but some electronic devices rely on these to allow working with convenient crystals. (When sending asynchronous data over 1200 bps synchronous modems, sometimes no stop bits could be sent over the wire, if the source clock was fast, as, being synchronous, there was no option to shorten the stop bit. Stop bits were re-inserted before creating the baseband output; I believe they ran the output clock fast to ensure that this worked.) Longer stop bits just reduce the maximum rate (characters per second) that you can send data. And give better recovery from false start bits - not a problem you should have on a short piece of wire. Incidentally, 4800 baud is normally sent with one stop bit. As noted elsewhere, it is only really for mechanical devices that one needed longer ones, so it tends to be 110 and below (maybe 300) that uses 2, or for, 5 unit, Baudot, 1.5. -- David Woolley The Elecraft list is a forum for the discussion of topics related to Elecraft products and more general topics related ham radio List Guidelines http://www.elecraft.com/elecraft_list_guidelines.htm ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
[Elecraft] K2 - KIO2 stop bit oddity
Hey Folks, I've just finished assembling a KIO2 for my K2 (SN 3490, Firmware 2.04). It seems to be working, but it only works reliably when I set my terminal software to use 1 stop bit instead of 2. If I set my terminal to 2 stop bits, I get garbled data about 70% of the time. For example, the ID; command will return ID017, ID0, ID, ID01, etc. I've observed this behavior on both a Mac and a PC, so I don't think it's my terminal program. I tried the MacK2 program and it works extremely erratically, presumably because it assumes 2 stop bits. The KIO2 manual says to use 2 stop bits, but that 1 stop bit will also work. Before I dive into this, I thought I'd see if anyone else has experienced this problem. Thanks in advance for any advice. 73 Joe KB8AP ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
Re: [Elecraft] K2 - KIO2 stop bit oddity
Joe Planisky wrote: Well, that's just it: you can't change it on the K2, and the KIO2 manual says it should be 2 stop bits. You will normally find that 4800 baud tends to be set to 2 stop bits but everything else appears to be 1. I don't know why this is but it seems to be the norm. Ian 73 Joe KB8AP On May 14, 2008, at 1:43 AM, Larry Clay wrote: One stop bit is the normal default for most programs for serial communications. Hyperterminal in Windows XP defaults to this. Also the KIO2 manual says that one stop bit works also. The main thing is that both the K2 and control program are set the same. Larry KB5DXY ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com -- Ian J Maude, G0VGS SysOp GB7MBC DX Cluster Member RSGB, GQRP K2 #4044 |K3 #455 ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
Re: [Elecraft] K2 - KIO2 stop bit oddity
Well, that's just it: you can't change it on the K2, and the KIO2 manual says it should be 2 stop bits. 73 Joe KB8AP On May 14, 2008, at 1:43 AM, Larry Clay wrote: One stop bit is the normal default for most programs for serial communications. Hyperterminal in Windows XP defaults to this. Also the KIO2 manual says that one stop bit works also. The main thing is that both the K2 and control program are set the same. Larry KB5DXY ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
Re: [Elecraft] K2 - KIO2 stop bit oddity
At 02:14 AM 5/14/2008, Joe Planisky wrote... extremely erratically, presumably because it assumes 2 stop bits. The KIO2 manual says to use 2 stop bits, but that 1 stop bit will also work. That is only possible if the K2 firmware sends 2 and receives 1. Since the source code isn't available to check, Elecraft will have to respond. Any device can send 2 (or more) stop bits, and any device can receive 1 stop bit. The extra bit(s) will just be considered marking time (extra idle time between characters). It would be strange for any modern device to require 2 stop bits. The option was originally used so that mechanical Teletype terminals would have enough time to cycle their mechanisms to an initial state between characters. That isn't an issue with any modern device (does anyone still use a Model 33 for RTTY?). If I set my terminal to 2 stop bits, I get garbled data about 70% of the time. For example, the ID; command will return ID017, ID0, ID, ID01, etc. That looks about right for a mismatch. If the sender is only sending 1 stop bit, the following start bit should result in a framing error, and NO character should be displayed. The inconsistency you see is likely the K2 marking time (busy with something else) between characters, which looks the same as the second stop bit to the receiver. ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
Re: [Elecraft] K2 - KIO2 stop bit oddity
On May 14, 2008, at 6:11 AM, Joe Planisky wrote: Well, that's just it: you can't change it on the K2, and the KIO2 manual says it should be 2 stop bits. The receiver's stop-bit setting needs to be greater than or equal to the stop bit setting of the transmitter. It is OK for the transmitter to send two stop bits and for the receiver to be set for one stop bit. It won't hurt a thing. Most UARTs use the stop bit setting to affect only the transmitter (RS-232 sending part of the device). The receiver will handle anything that is at least one bit-time long for a stop bit. Longer stop bits just reduce the maximum rate (characters per second) that you can send data. What may be happening is that the KIO2 is doing the UART in software. A longer period of time between characters (as represented by the extra stop bit) gives the processor more time to process the received character before the next character starts coming. -- 73 de Brian, WB6RQN Brian Lloyd - brian HYPHEN wb6rqn AT lloyd DOT com ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
Re: [Elecraft] K2 - KIO2 stop bit oddity
On May 14, 2008, at 6:21 AM, Ian J Maude wrote: Joe Planisky wrote: Well, that's just it: you can't change it on the K2, and the KIO2 manual says it should be 2 stop bits. You will normally find that 4800 baud tends to be set to 2 stop bits but everything else appears to be 1. I don't know why this is but it seems to be the norm. There is no reason for this. All the extra stop bit does is allow the receiver more time to process the most recently-received character before the next one arrives. -- 73 de Brian, WB6RQN Brian Lloyd - brian HYPHEN wb6rqn AT lloyd DOT com ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
