HLM8070 using Mitsubishi M50530 controller
Pollin.de offers a cheap HLM8070 display for about 3 €. The display comes with a Mitsubishi M50530 controller and utilise 4 rows and 16 columns. It is usefull small in size but on the other very good to read. The amount of 4 rows offers much space for information and even a menu line at the bottom. I bought some of these display nearly half a year ago and there was no source code for the Mitsubishi M50530 controller available on the net. So I created a little driver using AVR gcc and verifying the signals using my logic analyzer. At the end the driver follows the signal diagrams of the controller manual and works very well on different AVRs. When adapting the driver on other AVRs or platforms, be sure that the used I/O pins are available. The ATMega16 and ATMega32 have their JTAG interface on PORTC and it is enabled by default. The driver uses the display in 4-bit mode to reduce the used I/O pins of the controller. The control lines and data lines can be connected to different ports or together on one full 8 bit port. The port configuration has to be edited in the header file.