Tag Archives: Jack Eisenmann

Going 8-bit AVR with the DUO portable computer

Back in 2013, Bits & Pieces got up close and personal with Jack Eisenmann’s multi-core homebrew computer which is built around 16 ATMega328P microcontrollers. However, the talented Eisenmann didn’t stop there, as he subsequently decided to create the DUO tiny, a programmable computer based on Atmel’s ATtiny84.

Earlier this week, Eisenmann debuted the DUO portable, an inexpensive 8-bit computer based on Atmel’s ATMega1284 MCU. The platform is equipped with a black and white LCD output, along with a QWERTY keypad input.

Files are stored in a 64 KB EEPROM chip, with data written and read via a host computer through a serial interface.

All programs on the computer are written in a proprietary language dubbed “DPCL,” an acronym for DUO portable command language. Essentially, 

DPCL consists of plain ASCII commands interpreted by the ATMega1284. The programs are checked for syntax errors during runtime, with 12 KB of RAM allocated for DPCL programs.

Interested in learning more about the 8-bit AVR DUO portable? You can check out the project’s official page here.

This mini computer is designed around Atmel’s ATtiny84

Recently, we discussed how a talented Maker by the name of Jack Eisenmann designed a multi-core homebrew computer using 16 ATMega328P microcontrollers. And today? A programmable computer based on Atmel’s ATtiny84 dubbed the DUO tiny.

“The DUO system interprets its own proprietary programming language to run all applications. This language is called DUO Tiny Programming Language, or DTPL,” Eisenmann explained.

“Software is stored in EEPROM (AT24C1024B-PU25) and loaded through a serial interface. The computer is equipped with 4 buttons and a 102 by 64 pixel LCD display (EA DOGS102W-6). [Meanwhile], a three-pin port is available on the DUO Tiny board, [which] may be used to inspect and modify the contents of EEPROM.”

As the Hack A Day crew notes, Eisenmann’s project began on a breadboard, but as he brought each part into being it transitioned to a strip-board prototype – and finally the fab-house version seen in the video above.

Additional information about the Atmel-powered DUO tiny can be found here.

Atmel ATMegas power this homebrew 16-core computer

A talented Maker by the name of Jack Eisenmann has designed a multi-core homebrew computer using 16 ATMega328P microcontrollers.

“The DUO Mega is a multi-core 8-bit computer featuring a robust operating system. The goals of the system are to be efficient, reliable, easy to use, and open source,” Eisenmann explained in an extensive design breakdown posted on OstraCodfiles.com.

“The concepts of this computer should be expandable with more cores, additional memory and alternative processor models.”

According to Eisenmann, each core consists of a single ATMega microcontroller. More specifically, there are actually two types of core: worker and manager (15 worker cores + 1 manager = 16 total cores).

“Cores all share an 8 bit data bus. This data bus sends commands and information between cores. A worker core may not use the data bus unless permitted by the manager core. Each worker core is addressed by an 8 bit identifier,” he continued.

“When the machine starts up, the manager core poles every identifier to find worker cores. Then the manager loads instructions from flash memory into worker cores. The manager core may then behave as an interface for flash read and write operations.”

Eisenmann also noted that the DUO Mega is equipped with a single pool of shared memory in a 32 KB SRAM chip. Meaning, the manager core is responsible for access to shared memory – while also interfacing with peripheral devices.

On the software side, the OS user interface (UI) is based on a stack of windows, with  the DUO Mega supporting color text graphics and windows with 80 by 6 characters. All programs are written in Megaliter bytecode interpreted by the worker cores.

“Each program will run on at least one worker core. The number of worker cores allocated to a program depends on user preference. When the user opens a program, the operating system will first prompt the user for the number of cores to allocate,” said Eisenmann.

“One window will be dedicated to the operating system. This window is called the manager window, and cannot be closed. The manager window displays program information, a clock, files, directories and other useful information.”

Additional information about the Atmel-powered Duo Mega, including a full spec breakdown, can be found here.