All address lines of all chips must be connected to all corresponding address lines of all other chips, the exception being A15 which is described below, as it is used to select between RAM and EEPROM.All data lines of all chips must be connected to all corresponding data lines of all other chips.On the other hand, if you're just looking for a bit of reassurance that you're understanding everything, here's a quick list of everything that isn't included in the schematics below:
#Linux eprom programmer how to#
If you don't already know how to build a Z80 system, then you probably have issues far beyond this page lacking full schematics, but this page which also lacks full schematics may be of some help. The following schematics detail only the specifics of this programming interface, and assume that you otherwise know how to build a Z80 system. A logic analyzer or an oscilloscope might be helpful for debugging, but it isn't required, as careful attention to and verification of the wiring is sufficient to make the circuit operate. With these boards I was able to create my own FT240X boards for a mere $4.76 each, including the cost of all of the components.Īnyway, once you're past that hurdle, the rest isn't terribly difficult. (Here is the board in Postscript in case you want to make one as well.) With the recent introduction of the lower-cost FT240X, I created a set of Gerber files to be manufactured by for a mere $14 for ten.
Persuaded by those high prices (which matter a lot more when you realize this chip is so useful that you want ten of them) I designed my own board for the FT245RL which I made at home and which is shown in the photos above. However, there are development boards available for each, $20.00 for the FT245R and $23.75 for the FT240X. The largest hurdle to building this circuit is that it requires either an FT240X ($2.16) or an FT245R ($4.50), neither of which is available in DIP form. Here's a picture just in case you're wondering how much work is involved: