In the past the typical debug backdoor was a RS232 interface. I have for instance a BlueWave multi-DSP VME board, which has beside the VME and an ethernet board an RS 232 for console output. The reason RS232 was chosen for this purpose is obvious, cheap, small, available on most PCs, easy to implement and in a way foolproof (or at least problems such as wrong pinout can be easily fixed). I would expect that this role will is been taken over by USB now. The question is however, what type of service is used. Is there something established, or is this not necessary? I am aware that I can do a serial interface, jtag, etc. through USB, but this variety would counter the notion of "simply working without special SW" that the RS 232 provided. What do you think? Andreas
USB as standard debug interface
Started by ●March 18, 2011
Reply by ●March 18, 20112011-03-18
acd wrote:>In the past the typical debug backdoor was a RS232 interface. >I have for instance a BlueWave multi-DSP VME board, which has beside >the VME and an ethernet board an >RS 232 for console output. >The reason RS232 was chosen for this purpose is obvious, cheap, small, >available on most PCs, easy to implement and in a way foolproof (or at >least problems such as wrong pinout can be easily fixed). > >I would expect that this role will is been taken over by USB now. >The question is however, what type of service is used.See the thread "Do you still use "RS232" or something else?" starting 2011-01-14, Message-ID: <news:gec0j65r3h4d8la23gfvj1cknu5n0erp4g@z1.oliverbetz.de> Oliver -- Oliver Betz, Muenchen (oliverbetz.de)
Reply by ●March 18, 20112011-03-18
On Fri, 18 Mar 2011 09:52:10 -0700 (PDT), acd <acd4usenet@lycos.de> wrote:>In the past the typical debug backdoor was a RS232 interface. >I have for instance a BlueWave multi-DSP VME board, which has beside >the VME and an ethernet board an >RS 232 for console output. >The reason RS232 was chosen for this purpose is obvious, cheap, small, >available on most PCs, easy to implement and in a way foolproof (or at >least problems such as wrong pinout can be easily fixed). > >I would expect that this role will is been taken over by USB now. >The question is however, what type of service is used. >Is there something established, or is this not necessary? >I am aware that I can do a serial interface, jtag, etc. through USB, >but this variety would counter the >notion of "simply working without special SW" that the RS 232 >provided.A simple approach is to install an FT232R or Prolific interface as the "debug backdoor" instead of the serial level shifter and continue to use the embedded chip's UART just as before. Or, keep the serial and just use a USB-serial dongle. The only gotcha that I've seen to this is that WinXP might decide that it "recognizes" an FTDI/Prolific USB-serial connection as something other than a simple COM port if the port is active when the connection is plugged in. I have a board, for example, that's spitting out NMEA sentences over an FT232R that is *always* installed as a "Microsoft serial ballpoint" if the port is active when it's plugged in. The mouse cursor goes berserk. Much hilarity ensues. Do a 'net search for "USB serial ballpoint" and most of the hits are for this issue. @#$!$! Thank you, Microsoft. -- Rich Webb Norfolk, VA
Reply by ●March 18, 20112011-03-18
Rich Webb wrote:>The only gotcha that I've seen to this is that WinXP might decide that >it "recognizes" an FTDI/Prolific USB-serial connection as something >other than a simple COM port if the port is active when the connection >is plugged in. I have a board, for example, that's spitting out NMEA >sentences over an FT232R that is *always* installed as a "Microsoft >serial ballpoint" if the port is active when it's plugged in. The mouse >cursor goes berserk. Much hilarity ensues. Do a 'net search for "USB >serial ballpoint" and most of the hits are for this issue. @#$!$! Thank >you, Microsoft.Plus the constant annoyance of COM port numbers changing with the direction from which the wind is blowing. Today is COM739, tomorrow, who knows... -- Roberto Waltman [ Please reply to the group. Return address is invalid ]
Reply by ●March 18, 20112011-03-18
On Mar 18, 8:52=A0am, acd <acd4use...@lycos.de> wrote:> In the past the typical debug backdoor was a RS232 interface. > I have for instance a BlueWave multi-DSP VME board, which has beside > the VME and an ethernet board an > RS 232 for console output. > The reason RS232 was chosen for this purpose is obvious, cheap, small, > available on most PCs, easy to implement and in a way foolproof (or at > least problems such as wrong pinout can be easily fixed). > > I would expect that this role will is been taken over by USB now. > The question is however, what type of service is used. > Is there something established, or is this not necessary? > I am aware that I can do a serial interface, jtag, etc. through USB, > but this variety would counter the > notion of "simply working without special SW" that the RS 232 > provided. > > What do you think? > > AndreasUSB Virtual Com (CDC device), HID debug device and MSD device are popular. Android has all three over the same USB link. Actually, plus one for GPS NEMA serial.
Reply by ●March 18, 20112011-03-18
On 2011-03-18, Rich Webb <bbew.ar@mapson.nozirev.ten> wrote:> On Fri, 18 Mar 2011 09:52:10 -0700 (PDT), acd <acd4usenet@lycos.de> > wrote: > >>In the past the typical debug backdoor was a RS232 interface.> A simple approach is to install an FT232R or Prolific interface as > the "debug backdoor" instead of the serial level shifter and continue > to use the embedded chip's UART just as before.I find that works nicely. However, if you don't provide any identifying info (e.g. model string and serial number), dealing with more than one device at a time can be a hassle.> Or, keep the serial and just use a USB-serial dongle. > > The only gotcha that I've seen to this is that WinXP might decide > that it "recognizes" an FTDI/Prolific USB-serial connection as > something other than a simple COM port if the port is active when the > connection is plugged in. I have a board, for example, that's > spitting out NMEA sentences over an FT232R that is *always* installed > as a "Microsoft serial ballpoint" if the port is active when it's > plugged in.The same problem exists for non-USB serial ports under MS Windows. Any serial port that's receiving data as the OS boots is likely to be incorrectly detected as some sort of mouse.> The mouse cursor goes berserk. Much hilarity ensues. Do a 'net search > for "USB serial ballpoint" and most of the hits are for this issue. > @#$!$! Thank you, Microsoft.This has been a problem in Windows for decades. -- Grant Edwards grant.b.edwards Yow! A shapely CATHOLIC at SCHOOLGIRL is FIDGETING gmail.com inside my costume..
Reply by ●March 18, 20112011-03-18
On 2011-03-18, Roberto Waltman <usenet@rwaltman.com> wrote:> Rich Webb wrote: >>The only gotcha that I've seen to this is that WinXP might decide that >>it "recognizes" an FTDI/Prolific USB-serial connection as something >>other than a simple COM port if the port is active when the connection >>is plugged in. I have a board, for example, that's spitting out NMEA >>sentences over an FT232R that is *always* installed as a "Microsoft >>serial ballpoint" if the port is active when it's plugged in. The mouse >>cursor goes berserk. Much hilarity ensues. Do a 'net search for "USB >>serial ballpoint" and most of the hits are for this issue. @#$!$! Thank >>you, Microsoft. > > Plus the constant annoyance of COM port numbers changing with the > direction from which the wind is blowing. Today is COM739, tomorrow, > who knows...Add those to applications which refuse to talk to anything other than COM1-COM4, and you get one more reason to switch to Linux. -- Grant Edwards grant.b.edwards Yow! I'm young ... I'm at HEALTHY ... I can HIKE gmail.com THRU CAPT GROGAN'S LUMBAR REGIONS!
Reply by ●March 18, 20112011-03-18
On Mar 18, 10:45=A0am, Grant Edwards <inva...@invalid.invalid> wrote:> On 2011-03-18, Roberto Waltman <use...@rwaltman.com> wrote: > > > Rich Webb wrote: > >>The only gotcha that I've seen to this is that WinXP might decide that > >>it "recognizes" an FTDI/Prolific USB-serial connection as something > >>other than a simple COM port if the port is active when the connection > >>is plugged in. I have a board, for example, that's spitting out NMEA > >>sentences over an FT232R that is *always* installed as a "Microsoft > >>serial ballpoint" if the port is active when it's plugged in. The mouse > >>cursor goes berserk. Much hilarity ensues. Do a 'net search for "USB > >>serial ballpoint" and most of the hits are for this issue. @#$!$! Thank > >>you, Microsoft. > > > Plus the constant annoyance of COM port numbers changing with the > > direction from which the wind is blowing. Today is COM739, tomorrow, > > who knows...I hope you don't seriously have COM739. I have COM23 from PIC and COM24 from Android. The PIC is running USB host VCP. My test system is something like: Win XP PIC24 Android +--------------+ +------------+ | PDK ICD |-----| ICD VCP |-------------\ | PDK VCP |-----| VCP | | | | +------------+ +----------+ | ADK VCP |------------------------| VCP VCP| | ADK MSD |------------------------| MSD | | ADK ICD |------------------------| ICD | +--------------+ +----------+ PDK: PIC24 development Kit ADK: Android development Kit
Reply by ●March 18, 20112011-03-18
Grant Edwards wrote:>Add those to applications which refuse to talk to anything other than >COM1-COM4, and you get one more reason to switch to Linux.Like many others, I use Linux for my own tinkering, but can not switch at work. Many unavoidable development tools run only on MS-Windows. (From my current short list, Analog Devices VisualDSP, FPGA dev tools, VisualStudio for WinCE, etc.) -- Roberto Waltman [ Please reply to the group. Return address is invalid ]
Reply by ●March 18, 20112011-03-18
linnix wrote:>> > Plus the constant annoyance of COM port numbers changing with the >> > direction from which the wind is blowing. Today is COM739, tomorrow, >> > who knows... > >I hope you don't seriously have COM739.Not yet, but it is just a matter of time... ;) -- Roberto Waltman [ Please reply to the group. Return address is invalid ]