Post by thread:[PIC]: 16c745 with usb sample code doesnt work. dr

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'[PIC]: 16c745 with usb sample code doesnt work. dr'
2002\03\17@152646 by Justin Mierta

Hi. I'm a student here at Penn State, and am working on a group project to build a low-speed computer-based oscilloscope. To achieve this, we are using a PIC 16C745 to sample an analog signal, and transmit the data over the USB bus. We verified that the microcontroller (uC) worked properly by making it toggle the output of a port -- so we know the uC is working properly. Next, we uploaded the sample code provided with the USB firmware (assembly version) into the chip, and wired it up exactly as described in the last page of the firmware's documentation. When we plugged the USB cable into the computer, the circuit powered up just fine using the USB's 5volt source. I also checked V-USB, and it is a good 3.3 volts. We tried running the chip with a 24 MHz crystal, and with the same 6 MHz resonator as drawn up in the firmware documentation. From the hardware side, everything looks like it should... On the computer, however, win98 recognizes that a new USB device is attached, called %USB\UNKNOWN.DeviceDesc%. It also says "no driver files loaded". The device manager initially has the device disabled. If we enable it, the device then appears as being "malfunctioning" with a yellow exclamation point next to it. We tried 2 win98 second-edition machines, and a win2k laptop -- they all respond the same way. Because everything appears to be functioning properly in the hardware, we are thinking this may be a driver problem. Is there a driver for windows we need to install to make the sample code work? Is there some debugging utilities you guys have that can help us determine the problem? Do you have any suggestions re: what may be wrong? Thank you very much for your time, Justin Mierta -- http://www.piclist.com hint: To leave the PICList spam_OUTpiclist-unsubscribe-requestTakeThisOuTmitvma.mit.edu

2002\03\17@155213 by michael brown

> Hi. I'm a student here at Penn State, and am working on a group project > to build a low-speed computer-based oscilloscope. To achieve this, we > are using a PIC 16C745 to sample an analog signal, and transmit the data > over the USB bus. >We verified that the microcontroller (uC) worked > properly by making it toggle the output of a port -- so we know the uC > is working properly. <GRIN> > Next, we uploaded the sample code provided with the USB firmware > (assembly version) into the chip, and wired it up exactly as described > in the last page of the firmware's documentation. When we plugged the > USB cable into the computer, the circuit powered up just fine using the > USB's 5volt source. I also checked V-USB, and it is a good 3.3 volts. > We tried running the chip with a 24 MHz crystal, and with the same 6 MHz > resonator as drawn up in the firmware documentation. From the hardware > side, everything looks like it should... If no smoke comes out, it's a good start. ;-) > On the computer, however, win98 recognizes that a new USB device is > attached, called %USB\UNKNOWN.DeviceDesc%. That means that it's probably working, but windows doesn't "recognize" the device. > It also says "no driver > files loaded". The device manager initially has the device disabled. If > we enable it, the device then appears as being "malfunctioning" with a > yellow exclamation point next to it. We tried 2 win98 second-edition > machines, and a win2k laptop -- they all respond the same way. It sounds to me like the device is working, but you aren't loading a driver. Are you just pressing "finish" and not loading a driver? This is precisely how windoze behaves when you skip loading a driver and winderz doesn't have one built in. It sounds like totally normal behavior, you just need a driver (or at the very least an .inf file for windows to be able to identify the device) > Because everything appears to be functioning properly in the hardware, > we are thinking this may be a driver problem. Is there a driver for > windows we need to install to make the sample code work? Is there some > debugging utilities you guys have that can help us determine the > problem? Do you have any suggestions re: what may be wrong? I think you need a driver or .inf file. > Thank you very much for your time, > Justin Mierta Your welcome. ;-) michael brown -- http://www.piclist.com hint: To leave the PICList .....piclist-unsubscribe-requestKILLspam@spam@mitvma.mit.edu

2002\03\17@160613 by Justin Mierta

ya know, that sounds very much like my assessment of the situation. however, the documentation explicitly states that windows will automatically install the driver -- the sample code is some kind of virtual mouse that, when you apply a voltage to a port, it moves the cursor on the screen a little. and the documentation states clearly that the driver is built into windows, and should be automatically handled. the only thing is that...well....wouldnt %USB\UNKNOWN.DeviceDesc% actually have a filled in value if windows was able to determine what type of device it was? it seems that it still is possible that the usb communication isnt working in general....oh well. do you (or anyone else) know of a *VERY* simple usb program i can download into the microcontroller that comes with an included driver? that way i can test this theory.... justin michael brown wrote: {Quote hidden}>>Hi. I'm a student here at Penn State, and am working on a group project >>to build a low-speed computer-based oscilloscope. To achieve this, we >>are using a PIC 16C745 to sample an analog signal, and transmit the data >>over the USB bus. >> > >>We verified that the microcontroller (uC) worked >>properly by making it toggle the output of a port -- so we know the uC >>is working properly. >> > ><GRIN> > >>Next, we uploaded the sample code provided with the USB firmware >>(assembly version) into the chip, and wired it up exactly as described >>in the last page of the firmware's documentation. When we plugged the >>USB cable into the computer, the circuit powered up just fine using the >>USB's 5volt source. I also checked V-USB, and it is a good 3.3 volts. >>We tried running the chip with a 24 MHz crystal, and with the same 6 MHz >>resonator as drawn up in the firmware documentation. From the hardware >>side, everything looks like it should... >> > >If no smoke comes out, it's a good start. ;-) > >>On the computer, however, win98 recognizes that a new USB device is >>attached, called %USB\UNKNOWN.DeviceDesc%. >> > >That means that it's probably working, but windows doesn't "recognize" the >device. > >> It also says "no driver >>files loaded". The device manager initially has the device disabled. If >>we enable it, the device then appears as being "malfunctioning" with a >>yellow exclamation point next to it. We tried 2 win98 second-edition >>machines, and a win2k laptop -- they all respond the same way. >> > >It sounds to me like the device is working, but you aren't loading a driver. >Are you just pressing "finish" and not loading a driver? This is precisely >how windoze behaves when you skip loading a driver and winderz doesn't have >one built in. It sounds like totally normal behavior, you just need a >driver (or at the very least an .inf file for windows to be able to identify >the device) > >>Because everything appears to be functioning properly in the hardware, >>we are thinking this may be a driver problem. Is there a driver for >>windows we need to install to make the sample code work? Is there some >>debugging utilities you guys have that can help us determine the >>problem? Do you have any suggestions re: what may be wrong? >> > >I think you need a driver or .inf file. > >>Thank you very much for your time, >>Justin Mierta >> > >Your welcome. ;-) > >michael brown > >-- >http://www.piclist.com hint: To leave the PICList >piclist-unsubscribe-requestKILLspammitvma.mit.edu > > -- http://www.piclist.com hint: To leave the PICList .....piclist-unsubscribe-requestKILLspam.....mitvma.mit.edu

2002\03\17@165637 by michael brown

> ya know, that sounds very much like my assessment of the situation. > however, the documentation explicitly states that windows will > automatically install the driver -- the sample code is some kind of > virtual mouse that, when you apply a voltage to a port, it moves the > cursor on the screen a little. and the documentation states clearly > that the driver is built into windows, and should be automatically handled. Hmmm.... > the only thing is that...well....wouldnt %USB\UNKNOWN.DeviceDesc% > actually have a filled in value if windows was able to determine what > type of device it was? it seems that it still is possible that the usb > communication isnt working in general....oh well. Not necessarily. With PnP devices in general and USB in specific this is what windows will display allot of time, if it doesn't recognize the PnP string. It will actually read some descriptive name string from the device and then hide it from you when it doesn't recognize the ID. This is why many new USB devices tell you to install their software first before hooking up the hardware, otherwise people end up with the non-working device manager device and windos doesn't seem to detect their device any more, and they don't know why. > do you (or anyone else) know of a *VERY* simple usb program i can > download into the microcontroller that comes with an included driver? > that way i can test this theory.... sorry, I sure don't. I don't develop anything for windoz, I just fix it for people. If you have control over the ID string that is sent to the pc, it sounds like maybe it's not being interpreted properly or maybe your sending something in the wrong endian order or it's otherwise jumbled??? But like I said, I don't do windows (as far as code writing goes, I have enough debugging problems as it is). ;-) {Quote hidden}> justin > > > michael brown wrote: > > >>Hi. I'm a student here at Penn State, and am working on a group project > >>to build a low-speed computer-based oscilloscope. To achieve this, we > >>are using a PIC 16C745 to sample an analog signal, and transmit the data > >>over the USB bus. > >> > > > >>We verified that the microcontroller (uC) worked > >>properly by making it toggle the output of a port -- so we know the uC > >>is working properly. > >> > > > ><GRIN> > > > >>Next, we uploaded the sample code provided with the USB firmware > >>(assembly version) into the chip, and wired it up exactly as described > >>in the last page of the firmware's documentation. When we plugged the > >>USB cable into the computer, the circuit powered up just fine using the > >>USB's 5volt source. I also checked V-USB, and it is a good 3.3 volts. > >>We tried running the chip with a 24 MHz crystal, and with the same 6 MHz > >>resonator as drawn up in the firmware documentation. From the hardware > >>side, everything looks like it should... > >> > > > >If no smoke comes out, it's a good start. ;-) > > > >>On the computer, however, win98 recognizes that a new USB device is > >>attached, called %USB\UNKNOWN.DeviceDesc%. > >> > > > >That means that it's probably working, but windows doesn't "recognize" the > >device. > > > >> It also says "no driver > >>files loaded". The device manager initially has the device disabled. If > >>we enable it, the device then appears as being "malfunctioning" with a > >>yellow exclamation point next to it. We tried 2 win98 second-edition > >>machines, and a win2k laptop -- they all respond the same way. > >> > > > >It sounds to me like the device is working, but you aren't loading a driver. > >Are you just pressing "finish" and not loading a driver? This is precisely > >how windoze behaves when you skip loading a driver and winderz doesn't have > >one built in. It sounds like totally normal behavior, you just need a > >driver (or at the very least an .inf file for windows to be able to identify {Quote hidden}> >the device) > > > >>Because everything appears to be functioning properly in the hardware, > >>we are thinking this may be a driver problem. Is there a driver for > >>windows we need to install to make the sample code work? Is there some > >>debugging utilities you guys have that can help us determine the > >>problem? Do you have any suggestions re: what may be wrong? > >> > > > >I think you need a driver or .inf file. > > > >>Thank you very much for your time, > >>Justin Mierta > >> > > > >Your welcome. ;-) > > > >michael brown > > > >-- > >http://www.piclist.com hint: To leave the PICList > >EraseMEpiclist-unsubscribe-requestspam_OUTTakeThisOuTmitvma.mit.edu> > > > > > > -- > http://www.piclist.com hint: To leave the PICList > piclist-unsubscribe-requestspam_OUTmitvma.mit.edu > > -- http://www.piclist.com hint: To leave the PICList @spam@piclist-unsubscribe-requestKILLspammitvma.mit.edu

2002\03\17@170316 by Bob Barr

On Sun, 17 Mar 2002 16:03:11 -0500, Justin Mierta wrote: <snip> > >do you (or anyone else) know of a *VERY* simple usb program i can >download into the microcontroller that comes with an included driver? > that way i can test this theory.... > The sample code on Microchip's site for the 16C745/765 includes complete MPLAB projects for testing your USB connection. These projects are provided in both C and assembly. The last time I looked they were named 'usb122asm.zip' and 'usb122c.zip'. A search should find them for you. The firmware enumerates and drives your mouse cursor around the screen. No additional driver is required for this to work. It worked for me first time, no problem at all on Win98se. Regards, Bob -- http://www.piclist.com hint: To leave the PICList KILLspampiclist-unsubscribe-requestKILLspammitvma.mit.edu

2002\03\17@174344 by Justin Mierta

yeah, this is what we've been talking about.....its not working, and the hardware looks fine, but the driver doesnt appear to be correct justin Bob Barr wrote: {Quote hidden}>On Sun, 17 Mar 2002 16:03:11 -0500, Justin Mierta wrote: > ><snip> > >>do you (or anyone else) know of a *VERY* simple usb program i can >>download into the microcontroller that comes with an included driver? >>that way i can test this theory.... >> > >The sample code on Microchip's site for the 16C745/765 includes >complete MPLAB projects for testing your USB connection. These >projects are provided in both C and assembly. > >The last time I looked they were named 'usb122asm.zip' and >'usb122c.zip'. A search should find them for you. > >The firmware enumerates and drives your mouse cursor around the >screen. No additional driver is required for this to work. It worked >for me first time, no problem at all on Win98se. > > >Regards, Bob > > >-- >http://www.piclist.com hint: To leave the PICList >RemoveMEpiclist-unsubscribe-requestTakeThisOuTmitvma.mit.edu > > -- http://www.piclist.com hint: To leave the PICList spamBeGonepiclist-unsubscribe-requestspamBeGonemitvma.mit.edu

2002\03\17@185709 by Bob Barr

On Sun, 17 Mar 2002 17:39:14 -0500, Justin Mierta wrote: >yeah, this is what we've been talking about.....its not working, and the >hardware looks fine, but the driver doesnt appear to be correct > On my system (Toshiba laptop), the device manager shows an entry for USB devices with two sub-entries, one for the USB controller card and one for the root hub. The following driver files were automagically loaded under Windows 98se. (Sorry, I don't recall if I needed to use my install CD or not. I may have had to.) Controller driver: C:\WINDOWS\SYSTEM32\DRIVERS\openhci.sys C:\WINDOWS\SYSTEM\VMM32.vxd [NTKERN.vxd] C:\WINDOWS\SYSTEM\USBUI.dll C:\WINDOWS\SYSTEM32\DRIVERS\usbhub.sys C:\WINDOWS\SYSTEM32\DRIVERS\usbd.sys It's listed as Microsoft's version 4.10.2222 driver. Root hub: C:\WINDOWS\SYSTEM\VMM32.vxd [NTKERN.vxd] C:\WINDOWS\SYSTEM32\DRIVERS\usbhub.sys You may want to remove the Device Manager's USB entry and try to let Plug-and-Pray re-install it. I have a bunch more info available under Device Manager. Let me know if you need it and I'll email it off-line if you'd like. Regards, Bob -- http://www.piclist.com hint: To leave the PICList TakeThisOuTpiclist-unsubscribe-requestEraseMEspam_OUTmitvma.mit.edu

2002\03\17@192242 by Olin Lathrop

> On the computer, however, win98 recognizes that a new USB device is > attached, called %USB\UNKNOWN.DeviceDesc%. It also says "no driver > files loaded". This makes sense because your hardware wakes up and identifies itself as something Windows doesn't have a driver for. You will need to write a Windows driver for your specific USB device. You can't access your device from an application without a driver. ******************************************************************** Olin Lathrop, embedded systems consultant in Littleton Massachusetts (978) 742-9014, RemoveMEolinTakeThisOuTembedinc.com, http://www.embedinc.com -- http://www.piclist.com hint: To leave the PICList piclist-unsubscribe-requestEraseME.....mitvma.mit.edu

2002\03\17@192303 by Olin Lathrop

2002\03\17@210355 by M. Adam Davis

It sounds to me like the program on the USB chip is a little messed up. Look for the string similar to %USB\UNKNOWN.DeviceDesc% in your source code. See if you can find source for the chip that is different - that string should identify the device as a generic HID mouse device of some sort, not a "%USB\UNKNOWN.DeviceDesc%" -Adam Justin Mierta wrote: {Quote hidden}> Hi. I'm a student here at Penn State, and am working on a group project > to build a low-speed computer-based oscilloscope. To achieve this, we > are using a PIC 16C745 to sample an analog signal, and transmit the data > over the USB bus. We verified that the microcontroller (uC) worked > properly by making it toggle the output of a port -- so we know the uC > is working properly. > > Next, we uploaded the sample code provided with the USB firmware > (assembly version) into the chip, and wired it up exactly as described > in the last page of the firmware's documentation. When we plugged the > USB cable into the computer, the circuit powered up just fine using the > USB's 5volt source. I also checked V-USB, and it is a good 3.3 volts. > We tried running the chip with a 24 MHz crystal, and with the same 6 MHz > resonator as drawn up in the firmware documentation. From the hardware > side, everything looks like it should... > > On the computer, however, win98 recognizes that a new USB device is > attached, called %USB\UNKNOWN.DeviceDesc%. It also says "no driver > files loaded". The device manager initially has the device disabled. If > we enable it, the device then appears as being "malfunctioning" with a > yellow exclamation point next to it. We tried 2 win98 second-edition > machines, and a win2k laptop -- they all respond the same way. > > Because everything appears to be functioning properly in the hardware, > we are thinking this may be a driver problem. Is there a driver for > windows we need to install to make the sample code work? Is there some > debugging utilities you guys have that can help us determine the > problem? Do you have any suggestions re: what may be wrong? > > Thank you very much for your time, > Justin Mierta > > -- > http://www.piclist.com hint: To leave the PICList > RemoveMEpiclist-unsubscribe-requestspam_OUTKILLspammitvma.mit.edu > > > > > -- http://www.piclist.com hint: To leave the PICList RemoveMEpiclist-unsubscribe-requestTakeThisOuTspammitvma.mit.edu

2002\03\17@230623 by Bob Ammerman

It sounds like you do not have the USB decriptors defined correctly inside the PIC. Bob Ammerman RAm Systems {Original Message removed}

2002\03\18@013708 by Justin Mierta

there's been a lot of suggestions similar to this, but....i'm using code VERBATIM from microchip's website. the code i'm using is the sample code showing how to use USB. has this code worked for anyone else? if it has, i think its probably not the code inside the pic.... justin Bob Ammerman wrote: >It sounds like you do not have the USB decriptors defined correctly inside >the PIC. > >Bob Ammerman >RAm Systems > > >{Original Message removed}

2002\03\18@030201 by Bob Barr

On Mon, 18 Mar 2002 01:34:30 -0500, Justin Mierta wrote: >there's been a lot of suggestions similar to this, but....i'm using code >VERBATIM from microchip's website. the code i'm using is the sample >code showing how to use USB. has this code worked for anyone else? if >it has, i think its probably not the code inside the pic.... > Yes, I can confirm that the assembly version of the sample code, exactly as supplied, does work. Regards, Bob -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads

2002\03\18@042819 by Bob Barr

On Sun, 17 Mar 2002 17:39:14 -0500, Justin Mierta wrote: > >yeah, this is what we've been talking about.....its not working, and the >hardware looks fine, but the driver doesnt appear to be correct Sorry, I forgot to include the device manager info for the USB device itself. Once the device has enumerated, a new entry appears for 'Human Interface Devices'. Under that entry is one for 'USB Human Interface Device'. The driver files listed for it are: C:\WINDOWS\SYSTEM32\DRIVERS\hidusb.sys C:\WINDOWS\SYSTEM\VMM32.VXD [ntkern.vxd] C:\WINDOWS\SYSTEM32\DRIVERS\HIDPARSE.SYS C:\WINDOWS\SYSTEM32\DRIVERS\HIDCLASS.SYS It's identified as the Microsoft driver dated 4-23-1999. The version is 4.10.2222 Note: This entry appears and disappears as the device is attached and detached. The hub devices thta I mentioned in my earlier email are always present. Regards, Bob -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads

2002\03\18@081827 by Olin Lathrop

> It sounds to me like the program on the USB chip is a little messed up. > Look for the string similar to > %USB\UNKNOWN.DeviceDesc% That string may be what Windows says whenever it doesn't have the device name it its tables. I doubt that this is what the device itself is saying to Windows. ******************************************************************** Olin Lathrop, embedded systems consultant in Littleton Massachusetts (978) 742-9014, EraseMEolinspamspamBeGoneembedinc.com, http://www.embedinc.com -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads

2002\03\18@085550 by michael brown

> > It sounds to me like the program on the USB chip is a little messed up. > > Look for the string similar to > > %USB\UNKNOWN.DeviceDesc% > > That string may be what Windows says whenever it doesn't have the device > name it its tables. I doubt that this is what the device itself is saying > to Windows. I concur. -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads

2002\03\18@121842 by Justin Mierta

ok, here's an update on my thinking process. after doing much reading, and getting verification that the documentation is correct, i'm going to start thinking along the lines of "everything the documentation says is exactly true, what could go wrong." this is what i came up with: capacitance. i'm bringing into question the /way/ i realized the circuit. i'm using a 5' usb cable, with a connector, and wirewrap to connect the connector to the associated caps and resisitors. if any of you have built the circuit shown in the firmware documentation, and it worked for you, please tell me how you did so. did you use wirewrap on a protoboard, or a breadboard, or a PCB? did you use a 5' or 3' cable? did you add any extra capacitors at the connector? justin -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads

2002\03\18@131119 by Bob Barr

On Mon, 18 Mar 2002 12:16:43 -0500, Justin Mierta wrote: >ok, here's an update on my thinking process. after doing much reading, >and getting verification that the documentation is correct, i'm going to >start thinking along the lines of "everything the documentation says is >exactly true, what could go wrong." this is what i came up with: >capacitance. > >i'm bringing into question the /way/ i realized the circuit. i'm using >a 5' usb cable, with a connector, and wirewrap to connect the connector >to the associated caps and resisitors. > >if any of you have built the circuit shown in the firmware >documentation, and it worked for you, please tell me how you did so. > did you use wirewrap on a protoboard, or a breadboard, or a PCB? did >you use a 5' or 3' cable? did you add any extra capacitors at the >connector? > I've used it on both a proto-board and hand wired board (built on perf-board). I've used both 3' and a 5' cables. What 'associated caps and resistors' are you referring to? The small series resistors in the D+ and D- lines are not required to get it to work. The 1.5k resistor from V sub USB to D- is required for the device to be recognized by the hub. The only cap that I have in the USB portion of the circuit is the 200uF from V sub USB to ground that Microchip recommends. The proto rev of our production board doesn't even have that and it was working flawlessly as far as I could tell. (I've added the cap just in case it's really needed.) Regards, Bob -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads

2002\03\18@142727 by Anton Zorn

----- Original Message ----- From: Bob Barr <RemoveMEbbarrKILLspamCALIFORNIA.COM> To: <PICLISTSTOPspamspam_OUTMITVMA.MIT.EDU> Sent: Monday, March 18, 2002 10:04 AM Subject: Re: [PIC]: 16c745 with usb sample code doesnt work. driver issue? > The only cap that I have in the USB portion of the circuit is the > 200uF from V sub USB to ground that Microchip recommends. The proto > rev of our production board doesn't even have that and it was working > flawlessly as far as I could tell. (I've added the cap just in case > it's really needed.) Microchip's erroneously spec'd 200 uF in the document that accompanied earlier versions of their sample code. That cap should be 200 nF, as in the Data Sheet (DS1124C page 71). -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads

2002\03\18@154659 by Bob Barr

On Mon, 18 Mar 2002 11:11:14 -0800, Anton Zorn wrote: >----- Original Message ----- >From: Bob Barr >To: <spamBeGonePICLISTSTOPspamEraseMEMITVMA.MIT.EDU> >Sent: Monday, March 18, 2002 10:04 AM >Subject: Re: [PIC]: 16c745 with usb sample code doesnt work. driver issue? > > > >> The only cap that I have in the USB portion of the circuit is the >> 200uF from V sub USB to ground that Microchip recommends. The proto >> rev of our production board doesn't even have that and it was working >> flawlessly as far as I could tell. (I've added the cap just in case >> it's really needed.) > >Microchip's erroneously spec'd 200 uF in the document that accompanied >earlier versions of their sample code. That cap should be 200 nF, as in the >Data Sheet (DS1124C page 71). Thanks for that info. I missed that change. As a side note, does anyone else get irritated with the use of 'nF' for caps? I think that I would have noticed a change from 200 uF to 0.2 uF. The 200 uF to 200 nF change is a lot harder to spot, especially with my old eyes. :=) Regards, Bob -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads

2002\03\18@155536 by Spehro Pefhany

At 12:42 PM 3/18/02 -0800, you wrote: >As a side note, does anyone else get irritated with the use of 'nF' >for caps? I think that I would have noticed a change from 200 uF to >0.2 uF. The 200 uF to 200 nF change is a lot harder to spot, >especially with my old eyes. :=) I like nF. Gets rid of the 0.xx notation totally, and good riddance. 22n is much nicer than 0.022uF. I blame resistance to it on NIH Euro-phobia. I like 4K7 for 4.7K ohms, too. Best regards, Spehro Pefhany --"it's the network..." "The Journey is the reward" KILLspamspeffspamBeGoneinterlog.com Info for manufacturers: http://www.trexon.com Embedded software/hardware/analog Info for designers: http://www.speff.com 9/11 United we Stand -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads

2002\03\18@161914 by Bob Barr

On Mon, 18 Mar 2002 16:04:08 -0500, Spehro Pefhany wrote: >At 12:42 PM 3/18/02 -0800, you wrote: > >>As a side note, does anyone else get irritated with the use of 'nF' >>for caps? I think that I would have noticed a change from 200 uF to >>0.2 uF. The 200 uF to 200 nF change is a lot harder to spot, >>especially with my old eyes. :=) > >I like nF. Gets rid of the 0.xx notation totally, and good riddance. >22n is much nicer than 0.022uF. I blame resistance to it on NIH >Euro-phobia. > You're probably right about the Euro-phobia but I just don't think in terms of nF. I find the 0.xx uF notation more readable. If the letters 'n' and 'u' were easier to distinguish (especially on small, photocopied or smudged schematics), it would be a lot easier. >I like 4K7 for 4.7K ohms, too. So do I. I find that the xKx notation improves readability. Regards, Bob -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads

2002\03\18@184327 by Justin Mierta

thanks! that fixed it! justin Anton Zorn wrote: {Quote hidden}>----- Original Message ----- >From: Bob Barr <EraseMEbbarrEraseMECALIFORNIA.COM> >To: <@spam@PICLIST@spam@spam_OUTMITVMA.MIT.EDU> >Sent: Monday, March 18, 2002 10:04 AM >Subject: Re: [PIC]: 16c745 with usb sample code doesnt work. driver issue? > > > >>The only cap that I have in the USB portion of the circuit is the >>200uF from V sub USB to ground that Microchip recommends. The proto >>rev of our production board doesn't even have that and it was working >>flawlessly as far as I could tell. (I've added the cap just in case >>it's really needed.) >> > >Microchip's erroneously spec'd 200 uF in the document that accompanied >earlier versions of their sample code. That cap should be 200 nF, as in the >Data Sheet (DS1124C page 71). > >-- >http://www.piclist.com hint: PICList Posts must start with ONE topic: >[PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads > > -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads

2002\03\18@185528 by Bob Barr

On Mon, 18 Mar 2002 18:41:00 -0500, Justin Mierta wrote: >thanks! that fixed it! > What did you do to fix it? Did you change it from using a 200 uF cap to a 200 nF cap? Or did you add the cap where there was't one before? I've had the circuit working with no cap, 200 uF and (now) 200 nF. Maybe I was just lucky?? Regards, Bob > >Anton Zorn wrote: > >>{Original Message removed}

2002\03\18@212020 by Olin Lathrop

>> As a side note, does anyone else get irritated with the use of 'nF' for caps? I think that I would have noticed a change from 200 uF to 0.2 uF. The 200 uF to 200 nF change is a lot harder to spot, especially with my old eyes. :=) << I think it's about time that the standard power of 1000 prefixes are used for Farads as anything else. Yes, for a while I had to think ".1uF" everytime I saw "100nF", but I've made a deliberate attempt to use nF and am now quite used to it. Now if we could just dispense as easily with feet, inches, yards, palms, furlongs, pennyweights, fathoms, barrels, miles, etc, etc, etc, ... ******************************************************************** Olin Lathrop, embedded systems consultant in Littleton Massachusetts (978) 742-9014, spamBeGoneolinKILLspamembedinc.com, http://www.embedinc.com -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads

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