Intrakeyboard coupling and transposition control for a keyboard musical instrument

In a keyboard operated electronic musical instrument in which musical sounds are generated in response to activation of keyboard switches, the keyboard switches corresponding to notes arranged in groups corresponding to musical octaves and in which a key detect and assignor circuit stores data indicating the note to be generated in response to the activation of any selected keyboard switch, the keyboard detect and assignor circuit having an automatic transposing control comprising:

• a clock means for creating clock time signals, group counter means for counting said clock time signals modulo the number of musical octaves in a keyboard, a gating means responsive to the contents of said group counter for scanning the keyboard switches in groups to generate status signals representing the status of said keyboard switches for each group in succession on a common group of output lines, each line corresponding to a different note in a musical octave, status memory means for receiving and storing data from said group of output lines in parallel to be thereafter read out, the memory means receiving the states of the status signals for each group in succession, and transposing means for switching said common group of output lines relative to the inputs to said status memory means whereby the status signals on said output lines can be stored in selected locations in said status memory means to thereby cause the automatic transposition of said keyboard switches relative to the assigned locations in the status memory means.

In a keyboard operated electronic musical instrument in which each key operates a switch to produce a status signal indicating whether the key is depressed or released, a key detect and assignor circuit having an automatic transposing control for storing data indicating a note to be generated in response to operation of any selected key on the keyboard, the key detect and assignor circuit comprising:

• means including a group counter and means periodically advancing the counter by one count for connecting groups of key-operated switches in succession with each count of the counter to a common group of output lines, there being one output line per switch in each group, whereby switch status signals for the switches in each of the groups in sequence are provided on respective ones of the output lines in parallel with each successive count of the group counter, a plurality of status registers, one register for each output line, each register storing the status of one key in each group, a note counter for successively identifying all of the notes in a group as the note counter advances, transposing means for connecting said common group of output lines to the inputs of any selected ones of the registers, whereby any selected key in each of the groups can be connected with any particular register, the status registers storing the status of the switches to which respective registers are connected by the transposing means, means responsive to a change in the status signal from operation of any of said keys on any of said output lines relative to the status of the corresponding key stored in the associated register for interrupting the counting of the group counter and starting the counting of the note counter, an assignment memory, means controlled by the note counter for scanning the inputs to the registers from the transposition means in a fixed sequence, and means for storing the contents of the note counter and group counter in the assignment memory when a scanned input line indicates the associated key is depressed and comparison with the status in the register connected with a particular key by the transposing means indicates a change in status.