Is it common to receive bad chips 3 out of 5 no less? Or could there be something I'm doing wrong? As I say, I can succesfully burn 2 of them, so I'm sure there's no problem with the programmer or software.
Thanks for any ideas you may be able to offer. Joel Rainville New Member. Daz said:. Click to expand It is not common to receive bad chips, actually that should never happen :!
As Joel said, you might be operating in out-of-specification values, so that manufacturing tolerances play some role here. Try to re-do your programmer or even look for paralel type one. Great tips guys, thanks so much for the quick response.
Sounds like I need to build a new programmer. I'll also look into the other PICs that you suggest. I thought the 16F84A seemed like a good entry-level with a lot of community support. But now that my feet are wet I may be ready to try another chip. Thanks again! Take note of the errors. Do the verify errors all at Address or they occured in later addresses but in random locations different each time?
Do a manual erase and then program. If you get verify errors then erase and program again. Does the error occurs at the same place? Is it anywhere near 4. Is it anywhere near 12VV? Now check again with a PIC in the socket, does the above voltages drops lower a lot? Someone Electro New Member. You beter get an newer chip that that obsolete PIC16F The 4 and 20 Mhz verisons are the exsactly same chips.
Its just that the 4 Mhz didnt pass the tests as good as 20 Mhz ones. I also sugest an parallel port programer. I'm getting verify errors in the same place every time. In fact, when I do an erase, none of the data is changed. I know this because now 4 of the 5 PICs aren't working. So erase and write operations are not getting through to these 4 out of 5 chips. One chip is still working great.
Also my older 16F84 Non A chip is still working fine. A note, these 5 new chips are all 20 Mhz versions, so I wonder if they are more picky than my 4Mhz version.
Any suggestions of a good programmer schematic I might try to replace the JDM? I'd like to keep it RS if I can and also simplicity is my preference. Or do you think I'm better off getting in 5 new 16F84 - 4Mhz chips? Don't buy any more of 16F84 or 16F84A. They are old and expensive. The only reason of people buying 16F84 or 16F84A is the object code requirement. It works with no major issues. Try connects the Pin16 RA7 to Vss pin5 and see if situation improves.
This is the internal RC oscillator input in case you have enabled it. Glad to hear there is at last some good news. The voltage drop is normal as you are supposed to test the signal line one by one.
Can you try changing these options to see whether it helps? I think the sensible thing to do now is to fill in your physical location in the forum in hope that some people living in your area can offer to test one bad chip for you. All you need to do then is to mail it to him for the cost of local postage. You can also send the object code so he can help to program it for you should it turn out that the PIC is good afterall. Does the voltage goes from 4. If so, then it is highly likely that the three chips are bad.
Can you still read them? Nigel Goodwin said:. I am ok with that, I just wanted to make sure "Daz" will know what to do when he decides to use "new" instead of Follow-up Hi all, I just wanted to post a follow up and let you all know how things ended up with this. First off, thanks for all the help that everyone offered.
In the end I went with the advice to build a new programmer. I also replaced my 16F84's with 16F's and I love them. I've built my new programmer and it works on all the chips that weren't programming with the JDM.
So in summary, I highly recommend this particular programmer to anyone looking for a reasonable DIY programmer to build. Once again, thanks to everyone. It sounds like you were getting the same problem as I was.
You may like to check pic microcontroller tutorials. This is an 18 pin IC, the description of each pin are given below:. These 13 GPIO pins can be independently configured either as digital input or as digital output. Also, each pin can either supply or can absorb a maximum of 25mA current per pin.
So, accordingly, every pin can drive a LED easily but cannot drive any dc motor or relays. Because, current requirement for LED is generally less than 10mA and dc motor requires greater than 25mA. If you want to interface relay or dc motor, you have to use current driver ICs.
Like motor driver IC to interface motor and relay driver IC to interface single of multiple relays. Each of these pins source and sinks 25mA current. With little careful, you can program the microcontroller deprived of eliminating it from the target board for example in-circuit. It contains 64 bytes memory that is mainly used to store data and 1K program memory specifies the capacity of code you can burn inside. Watchdog timer: This microcontroller has built-in Watchdog timer.
There is an internal timer located under the chip. You can make this timer enable or disable by programming. The timer is mainly used to rest the microcontroller when the program goes wrong or it may enter to the infinite loop. Registers: There are two types of registers which are as follow here. Timer : PIC16F84a contains one 8-bit timer that can be utilized in both ways i.
Furthermore, accompanies internal and external clock select capability. Sleep Mode: This mode is included the chip that produces a low current power down mode. The sleep mode can be removed using an interrupt, external reset, and watchdog timer.
Power on Reset: This feature is utilized in various other PIC microcontrollers when it is powered on. If there arises a problem in the chip, powering on the device will dismiss it from the loop of any malfunctioning in the device. This is also used in Central heating projects, Production of the temperature data logger, and gas sensor projects. Also used in security systems and setting up serial communication with other devices. The code written in the compiler creates a hex record that is transferred on the PIC Microcontroller.
Before accessing any register during the time of programming or program writing, you must need to select the particular bank which contains that register. Handling banks may be steep if you write the code in assembly language. Flash Memory: This consist of Flash memory based on 8-bit microcontroller packs. The same microcontroller device can be used for prototyping and production.
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