Post by thread:[PIC:]Re: Fried MCLR on 18f452?

Daniel Chia wrote : > > Hi, > > I recently built my own serial programmer for the > > 18F452 using the com84-style kind of programmer. I don't know that programmer, and you don't specificaly say, but it *does* support the 18F452, right ? > > i programmed it in IC-prog with JDM setting. > > However, my MCLR pin is behaving strangely. Its drawing > > about 13mA of current and if use a 4k7 to tie it high, the > > voltage at the pin is 0.6V! > > So right now i tie it directly high and everything appears to > > be okay... Appears yes, but you don't think it is okay, right ? :-) :-) Breadboard or PCB ? Anything else connected (intentionaly or by accident) the MCLR ? Tested with another 18F452 ? What is the rest of the setup looking like ? Jan-Erik. -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics

Hi, ----- Original Message ----- From: "Jan-Erik Soderholm" <jan-erik.soderholmKILLspamTELIA.COM> To: <.....PICLISTKILLspam.....MITVMA.MIT.EDU> Sent: Monday, June 21, 2004 19:18 Subject: Re: [PIC:]Re: Fried MCLR on 18f452? > Daniel Chia wrote : > > > > Hi, > > > I recently built my own serial programmer for the > > > 18F452 using the com84-style kind of programmer. > > I don't know that programmer, and you don't specificaly > say, but it *does* support the 18F452, right ? > The programmer is designed for a 16f877 i believe but as far as i know i think its compatible. Don't have anymore programmed 18f8452s on hand to test whether its the chip thats cooked.. > > > i programmed it in IC-prog with JDM setting. > > > However, my MCLR pin is behaving strangely. Its drawing > > > about 13mA of current and if use a 4k7 to tie it high, the > > > voltage at the pin is 0.6V! > > > So right now i tie it directly high and everything appears to > > > be okay... > > Appears yes, but you don't think it is okay, right ? :-) :-) Yeah, not being able to tie high the MCLR through a resistor is really wierd... I measured the 13mA by hooking up a multimeter from Vcc to the pin. > > Breadboard or PCB ? Breadboard > Anything else connected (intentionaly or by accident) > the MCLR ? Theres nothign else connect to the MCLR > Tested with another 18F452 ? > What is the rest of the setup looking like ? Erm i have a LM2940CT05 regulator supplying power. its connected to a wallwart kind of adaptor giving about 7 volts. > > Jan-Erik. > > -- > http://www.piclist.com hint: The list server can filter out subtopics > (like ads or off topics) for you. See http://www.piclist.com/#topics ------------------------------------------------------------------------ Daniel Chia "Genius is one percent inspiration and ninety-nine percent perspiration." - Thomas Edison E-mail: EraseMEdanielcjhspam_OUTTakeThisOuTyahoo.com.sg MSN: danstryder01spam_OUTyahoo.com.sg ------------------------------------------------------------------------ -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics