The disclosure relates to technology for configuring programmable logic devices having multiple programmable hardware units configurable in one or more functional modes. The programmable hardware units are coupled to independent switch devices (e.g., multiplexers) that select configuration patterns stored in a common and shared configuration memory. The configuration memory includes a set of configuration registers to store the configuration patterns, which configuration patterns correspond to the one or more functional modes. The configuration registers may be addressed using an index of addresses stored in memory that identify a select line in one of the switch devices for a particular programmable hardware unit. Each select line in a switch device corresponds to a particular one of the configuration registers storing the configuration pattern. The addressed configuration register is accessed to retrieve the configuration pattern and configure the programmable hardware unit.