Post by thread:12C508 vs. 16c84

This is probably a VERY stupid question but I get very confused when I read the docs on different PIC devices. I have used 16C84 and according to the docs it has EPROM memory. Still I don't need to UV erase and can reprograme the device as needed. ( I never understood why the C was not an F from the beginning. When I read about the 12C508 device I get the impression that is an EPROM device and that I need to erase it with UV light. Or does this chip erase/program just the same way as the 16C84? Can someone clear up my confusion!? Regards /Ake

Ake Hedman, eurosource wrote: > I have used 16C84 and according to the docs it has EPROM memory. Still I > don't need to UV erase and can reprograme the device as needed. ( I never > understood why the C was not an F from the beginning. > > When I read about the 12C508 device I get the impression that is an EPROM > device and that I need to erase it with UV light. Or does this chip > erase/program just the same way as the 16C84? The 16C84 is an EEPROM device. The non-volatile memory is electrically erasable , thus can be erased without UV light. The 16F84 is a FLASH memory device. The non-volatile memory is also electricall y erasable and does not require UV light. The 12C508/9 come in two flavors: 1) the 12C508-04/P which is a One Time Programmable (OTP) part. No erasures are possible under normal circumstances. 2) the 12C508-04/JW which is a UV-erasable windowed part. It may be erased usin g UV light. AFAIK the two parts (P and JW) are identical except for the case. Thus, the OTP part has an EPROM non-volatile memory, but lacks the window to allow for erasing. Michael ************************************************************************* When the way of the Tao is forgotten, kindness and ethics must be taught. Men must learn to pretend to be wise and good. -- Lao Tzu *************************************************************************

Dear Ake, your impression is ok. 16C(F)8X uses a kind of EE_PROM Technology while 12c508 uses E_PROM technology with OTP devices in plastic case and UV-erasable devices in a windowed cerdip package (Case = JW) ( an much mor expensiv ). Ake Hedman, eurosource wrote: > > This is probably a VERY stupid question but I get very confused when I read > the docs on different PIC devices. > > I have used 16C84 and according to the docs it has EPROM memory. Still I > don't need to UV erase and can reprograme the device as needed. ( I never > understood why the C was not an F from the beginning. I got confused by this too... > When I read about the 12C508 device I get the impression that is an EPROM > device and that I need to erase it with UV light. Or does this chip > erase/program just the same way as the 16C84? > > Can someone clear up my confusion!? > > Regards > /Ake