Behold this ATtiny85 based EEPROM programmer. It seems like a roundabout way of doing things, but [Quinn Dunki] wanted to build to her specifications using tools she had on hand. What she came up with is an ATtinyISP USB programmer, pushing data to an ATtiny85, which then programs an EEPROM chip with said data.
The hardware is the next module for her Veronica 6502 computer build. When we last saw that project [Quinn] was planning to add persistent storage for the operating firmware. This will be in the form of an EEPROM programmed with this device. Using ISP and an ATtiny as a go-between means that she should have no problems reflashing the OS without removing the chip. But it all depends on how she designs the interface.
For example, she blew a whole bunch of time troubleshooting the device because garbage data was being written to the chip. In the end, having her manual bus programmer hooked up during the flashing operation was the culprit. Lesson learned, it’s onward and upward with the build.
We’ve been featuring [Quinn’s] projects a lot lately. That’s in part because they’re really interesting, but also because she does such a great job of documenting her experience.
[Fezoj] likes to play around with microcontrollers and decided that he wanted to try a Bus Pirate as a new tool in his adventures. Since it’s open hardware he had his own board made and populated it himself. The trouble is, he works only with AVR chips and doesn’t have a PIC programmer. No problem, he figured out how to flash the PIC24FJ using an ATmega8.
To get started, he grabbed a copy of the flash programming specifications from Microchip. Once he had implemented the protocol in the AVR code, it was just a matter of getting the downloaded PIC firmware to the AVR. An RS232 chip gives him the serial connection he needs, with the help of his own programming software written with Visual Studio.
It’s not a robust solution for prototyping on the PIC platform, but maybe it could be developed for that purpose. For now, all he needed was a bootloader so that he could flash the Bus Pirate via a USB connection.
[via Dangerous Prototypes]
[jethomson] sent in a build he’s been working on that turns an inexpensive AVR programmer into a development board. The build is based on the very affordable USBasp programmer that’s based on an ATmega8. With hundreds of these boards available from China for less than a Hamilton, we’re wondering how soon it will be before we see these boards end up in other projects.
After fiddling with the AVR fuse settings, [jethomson] managed to burn some code to the microcontroller. After that, all that was required to upload software to the programmer is a bit of solder, a push button, and an external programmer. [jethomson] also managed to make this little AVR programmer compatible with the Arduino environment with a small addition to the boards.txt file.
[jethomson] included a few bits of software as an example – he ported the haunted USB cable and adapted the USB business card to print out, “All work and no play makes Jack a dull boy.” Nice work, and we can’t wait to see it in future projects.
If you’re planning to do some hacking with CPLD or FPGA chips you’ll need a way to program them. JTAG is one of the options and here’s a cheap method that uses the serial port (translated).
This method requires only four signals (TDI, TMS, TCK and TDO) plus ground. But the problem is that an RS232 serial port operates with 12V logic levels and the JTAG side of the programmer needs to operate with the logic levels native to the device you’re programming. Commercial programmers use a level convert IC to take care of this for you, but that doesn’t mesh with the cheap goal of this project. Instead, [Nicholas] uses Zener diodes and voltage dividers to make the conversion. There is also an LED for each data signal to give some feedback if you’re having trouble.
You can use this along with a programming application that [Nicholas] whipped up using Visual Studio. It works well via the serial port, but he did try programming with a USB-to-Serial dongle. He found that this method slows the process down to an unbearable 5-minutes. Take a look, maybe you can help to get that sloth-like programming up to a manageable speed.
A common complaints of beginners to microcontroller programming is the availability of DIY tools that do not require a parallel port. Using not much more than a couple of 74xx series chips and some protoboard, [Rue] was able to create an AVR programmer for less than the cost of some chips it can program – giving parallel programmers a run for thier money. [Rue] used Linux treat the ubiquitous PATA/IDE port as a parallel port. By having avrdude treat the programmer as an Atmel STK200, [Rue] was able to upload a blinky program to his AVR microcontroller through ISP. If anybody can think of an even lower cost unconventional solution give us a shout.
Versaloon is an open source, USB connected project, that centers around an STM32 processor and provides a standard JTAG pinout. Above you see the Nano version which has a 10-pin JTAG connector, but there is also a 20-pin option on the Handy model. Great, another JTAG programmer. Well this can do a bit more than that. With a bit of help from the software it has been turned into a programmer for ten different types of hardware. Obviously this should be able to program anything that works with the JTAG protocol, but the script adapts it to work as an In System (or In Circuit) Programmer too. So far the list of programming targets includes STM32, LPC1000, LPC900, STM8, AR8, MSP430, and a few others.
We had some trouble finding an actual picture of this hardware. If you’ve got one, snap a picture and leave a link to it in the comments along with your thoughts on the device.
In the last installment of our tutorial series we built a simple circuit on a breadboard and programmed an ATmega168 to make it run. That proves that you know how to follow directions, but the eureka moments of doing everything yourself are on the way. This time around you will get down and dirty with the datasheet, learning where each line of the sample code came from, and give your recently installed compiler a test drive. We will:
- Talk about bitwise operators and how they work when coding for microcontrollers
- Discuss C code shorthand
- Review the sample code from Part 2 and talk about what each line of code does
- Learn to compile code
If this is the first you’ve heard about our AVR Programming series, head back to Part 1 and start from the beginning. Otherwise, take a deep breath and we’ll being after the break.
Continue reading “AVR Programming 03: Reading and compiling code”