![]() ![]() In other words, when you plug one of them, it shows up as a printer. ![]() However, after searching a bit more, I found that all such adapters behave as a USB printer. Inside one of the connectors there is some circuitry to actually do the conversion.Īt first, that seems like a good solution. They are a cable with a USB connector at one end and a DB-25 connector at the other end. If you search the web (or your local computer hardware store), you will find quite a few USB Parallel Port adapters. How can I program my AVR microcontroller? Using a USB Parallel port adapter Well, I don’t have those ancient ports anymore in my computer. In a nutshell, you write bytes at one end, they are transmitted using the RS-232 protocol, and they arrive at the other end. On the other hand, once you had RS-232 implemented, using the serial port became quite simple. The serial port was a bit more complicated because it implemented the RS-232 protocol, and thus it required a non-trivial hardware. It also had a few special pins that could be used for reading data. Pretty damn simple, and quite useful for small DIY hacks. So, the software could write a byte to the parallel port, and each one of those pins would be driven high or low. It had 8 output pins, each one mapped to one bit from a byte. ![]() The parallel port was great for hobbyist projects because the hardware for interfacing with it was trivial. And nobody cared, because nobody used them anymore. What’s more, they take up a lot of space in the back panel, space that was needed for all those new features added to the motherboards.Īnd then those ancient ports disappeared from the modern computers. And also having on-board sound card, and on-board video card, and on-board ethernet adapter… And those “ancient” parallel and serial ports were becoming more and more useless. And gradually the motherboards started having more and more USB ports. Even laptops had such ports (or had a “docking station” that added those ports to the laptop). And I end up building (and buying) the USBasp ( Wayback Machine) programmer.īack in the early days, basically all computers had a parallel port (also called printer port) and a serial port. However, today it is difficult to find a computer that has a parallel port, and thus I needed to revisit this topic of AVR programmers. Almost 4 years later, I started using AVR microcontrollers again. ![]()
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