-------------------------------------------------- From: "Drew Maurer" Sent: Thursday, July 29, 2010 3:43 AM To: "Microcontroller discussion list - Public." Subject: Re: [PIC] 16F747 UART errors > Nope, all voltages look fine. > > I just bought a new USB-serial dongle... same problem. Maddening!! Have you tried it on another PC yet? (preferably with a proper serial port)= =20 Making sure it's not the PC side would help, may be an issue with your PCs= =20 USB hub/drivers etc. When testing a bit banged serial a little while back on a 16F636 I used a=20 little test program to send a couple of characters in a tight loop so I=20 could examine the timing on a scope - maybe you could try this, send a loop= =20 of a few characters and see if there is any evidence of timing problems tha= t=20 could cause bytes to be dropped. You can also just hold a key down on the P= C=20 and examine timings the other way for comparison. Also, if you have a PicKit2 handy you could use the UART tool to connect to= =20 the PIC - this should be pretty much guaranteed to work so if you are still= =20 getting problems you can be almost certain it's on the PIC side. Just in case if you have another PIC handy you could give that a go too - I= =20 was helping a chap some time ago with similar issues and using a different= =20 PIC sorted the problem (the PICs clock appeared to be playing up for some=20 reason, causing timing problems) I know this kind of thing is a very rare=20 occurrence but eliminating everything helps. I'm assuming power supply, pin voltages, clock speed etc have all been=20 tested, bypass caps are being used etc etc.=20 --=20 http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .