Post by thread:Tait's Programmer flavours

Hello PIC lovers: I need to debug my PIC programming gear at once or I'll go nuts soon. The last I've built is David Tait's Simple 16c84 Programmer dated 20/06/95. I used a rectangular PCB made by Michael Laidlaw that uses an external programming power supply and a male 9-pin port. I've checked all connections and they seem to be OK. I'm using a cable that's less than 3 feet long. VPP levels are given by a power supply of 24V DC 1A current. Computer is a P-166 (ECP parallel port). I observe the same strange behaviour with programmer running on at least five different kinds of software (PicProg2, ProPic, P16Pro, Cybertech, Pix). The PIC16F84 yields OK on erasure and blank test. Apparently, it reads the PIC with no problem. Even the leds flash at the right time. But actual writing is impossible. I always get errors on Data verify, Program verify and Fuse verify. So data always remain the same on the PIC, I wasn't able to modify a single cell. I don't have documentation for this particular programmer and I'm confused with so many variants. I could device at least 4 variants of Tait's own programmer: Tait 6, Tait 6T, Tait 7, Tait 7T, and that's just the beginning! Anybody knows the difference between them? Can anybody complete this chart for the programmer? Vdd Vpp Clock DataIn DataOut P.Port D? D2 D3 D1 D0? Ack? Inverted Yes? Yes? Yes Yes Yes Low/High On/Off? ? ? ? Pix turns the Code Protect flag on when I read the Pic. If this flag were actually on, can I erase the Pic anyway? (I just wonder if this flag has something to do with my burning problem...)(I wouldn't be surprised if I knew I screwd it up! Believe me, Microchip stuff is really hard. A Motorola HC11 wouldn't have survived my "extreme enviroment testing conditions" ;-) P.D.: Sorry that I left multimeter measurements out. I send my old analog model to the after life and I'm now planning to buy a digital one next week-end. P.D.2: I've seen crowded lists before but this one wins my editor's choice by far! More than a hundred messages a day! I must be already nuts! -------------------------------------------------- "Hiroshima '45 Tsjernobyl '86 ... Windows '95" netQ <spam_OUTnetquakeTakeThisOuTinnocent.com>