Hi Dennis, Espero que tus cosas marchen bien. Dennis Crawley wrote: > > I want to practice 8051 programming. I have a lots of boards with this micro > and it seems it could use an external program memory pulling up or down some > pin. (Manual says). The micros I have seems OTP, I must go to external. Which chip number/manufacturer is in your boards? There are many MCS-51 "grandsons" out there, from many companies. > Well I want to hear your suggestions, in how to make a simple "external" > programmer. My first thought is to make a board with a pic :) an a flash > memory. The pic receives, via RS232, the .hex and load the program to the > flash. Then reset the 8051. If you want do use the PC serial port, it's a good idea. However, the LPT-based approaches are more simple. Be aware that "traditional" MCS-51 derivatives needs to be programmed in parallel, through the use of its data/address buses, and they need high voltage Vpp. The newest, In-System Programmable clones needs a really simple hw interface. > My intention is to learn with a real 8051 type micro,... not virtual (I have > at least two software simulators). > Any clue on this I'll appreciate. > Dennis Crawley Well, in our country some Atmel chips are the more easily available 8051 derivatives. I recommend you the in-system programmable ones, such as the AT89S52 (around US$3) and the AT89S8252, with data EEPROM, SPI, two DPTR's (around US$9). Check out the datasheets at atmel.com . Where? Microelectronica SH and Electrocomponentes . For these Atmel chips there are many programmers out there in the net (e.g.: AEC-ISP), very simple (only buffers for the ISP serial programming lines, from LPT port to the uC) just do a Google search. Here at our School i'm a teaching assistant in the microcontroller's introductory course, and we use mainly the Atmel chips. If you're interested, i can share a brief document with the hw details for an ISP programmer that works with Atmel's free programming windoze sw, "AT89ISP". Best regards, S.- _______________________________________________ http://www.piclist.com View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist