On Thu, 7 May 1998 13:20:48 +0200 Zoltan Perhacs writes: >Can i program the EPROM based PIC microcontrollers with serial mode >programming ? >Is the serial mode programming just for the OTP and FLASH PICs ? Most of the PIC line is EPROM based. An OTP PIC is just an EPROM PIC in a black plastic package that can't be erased. It is *exactly* the same chip found in the "JW" ceramic package with a window so it can be erased. So any circuit that can program an OTP chip can also program a JW window version of the same chip. The main thing to look out for with homemade programmers is that the 16F84 "Flash" chips aren't too particular about the high voltage applied to the MCLR pin to program them. The actual programming voltage comes from an internal voltage multiplier. But the EPROM chips are sensitive to the MCLR voltage, since this voltage is used directly to program the EPROM array. A programmer for them needs to apply a well-regulated voltage with about 50 mA current capability. Also the '84s internally time the programming cycle but the EPROM ones don't. (The voltage booster and internal timer need to be present in the 16X84 to support the data EEPROM during run-time.) That's why so many of the homemade programmers are only suitable for the '84s. _____________________________________________________________________ You don't need to buy Internet access to use free Internet e-mail. Get completely free e-mail from Juno at http://www.juno.com Or call Juno at (800) 654-JUNO [654-5866]