$D405/54277/SID+5:   Voice 1: Attack / Decay Cycle Control

   +----------+---------------------------------------------------+
   | Bits 7-4 |   Select Attack Cycle Duration: 0-15              |
   | Bits 3-0 |   Select Decay Cycle Duration: 0-15               |
   +----------+---------------------------------------------------+

   This register is write-only!

   See also: ADR-Rates