MATRIXSYNTH: Building a Drum Computer for the RetroChallenge 2021/11

Sunday, October 17, 2021

Building a Drum Computer for the RetroChallenge 2021/11

video upload by Michael Wessel

This one is in via Michael Wessel.

"This is my entry for the RetroChallenge 2021/10.

My Hackaday project page explains some more details"

And via Hackaday:

"In this episode, I extend the pattern-based drum computer to full 16 steps / beats (4 bars x 4 beats), and tailor for real time drum pattern input (like a real drum computer).

This requires inputting data from the keypad using the KIN (Keyboard Input) op-code, whilst playing back the pattern, and hence isn't possible with the standard Microtronic KIN. Thus, I implemented a non-blocking KIN behavior. Utilizing 2 more vacuous op-codes, I can now toggle between the standard blocking KIN input behavior, and the new non-blocking behavior.

The op-codes for determining the KIN mode of operation are 3F0 (blocking KIN mode) and 3F1 (non-blocking KIN mode). By default, the Microtronic only uses blocking KIN. The vacuous op-codes 3F0 and 3F1 are idempotent immediate AND (ANDI) op-codes, i.e., the operand 0xF = 0b1111 = 15 is idempotent for 4bit registers, and hence, no (existing or new) program would ever use them. So it is safe to assign the mode toggling extra side-effect to them.

In general, the following vacuous op-codes are available for side effect extension:

MOV x,x: copy register x onto register x, 0xx
ADDI 0,x: add 0 to register x, 50x
SUBI 0,x: subtract 0 from register x, 70x
ANDI F,x: bitwise AND of register x with F, 3Fx"

Full details on Hackaday.

No comments:

Post a Comment

Comments are moderated for spam and negativity. Comments do not appear immediately and are published throughout the day.


Patch n Tweak

© Matrixsynth - All posts are presented here for informative, historical and educative purposes as applicable within fair use.
MATRIXSYNTH is supported by affiliate links that use cookies to track clickthroughs and sales. See the privacy policy for details.