Tony of Electrokraft has just released a set of new products: Super Synth Drums the DrumAxe. Both work in conjunction with an NES system running custom software called Super Synth Drums. The software translates button presses into Drum sounds that are being synthesized by the NES itself. Everything was written in 6502 assembly language and burned to a ROM by Tony. His main resources for learning ASM were books like “Atari Roots” by Mark Andrews and others written in the early 1980′s, as well as help from people at the NESDev.com website.
In the heart of the circuit is a PIC microcontroller driving a 4021 “parallel to serial” shift register. Multiple input buttons or in this case touch sensors are encoded to single serial output that is understood by the Nintendo System. The Sonic DrumAxe essentially replaces gamepad #1 on the NES. The second gamepad can be used to add a variety of pulsing/looping effects. Unfortunately given the current legacy status of the NES hardware, the actual NES connectors are hard to come by without cannibalizing and existing system, so Tony devised an RCA style setup with an OEM DIN to RCA cable. 4 RCA jacks on the NES correspond to the Clock, Latch, DATA, and Ground required for sending bytes to the NES CPU.
There will be an upcoming tutorial demonstrating how the Sonic Drum Axe’s circuit was made and how it’s connected to the NES. Also for those who have already purchased the Super Synth Cart or are thinking about it, please keep in mind that in the future Electrokraft may offer free ROM upgrades, which will include more sounds and features! Harmony Central just did a wrote up as well.