Pre-designed configurable platforms, possessing microprocessors, memories, and numerous peripherals on a single chip, are increasing in popularity in embedded system design. Platform configurability enables use in more products, which results in lower cost platforms due to higher volume production. Common configurable features include voltage scaling and cache organization. We introduce a new bus architecture that can be configured for normal performance or low power. The additional hardware that provides this configurability imposes almost no performance overhead in normal mode compared to a non-configurable bus. We show the substantial range of power and performances that such a bus provides, and we show that the low-power configuration can result in energy savings, using a set of benchmarks. Keywords Bus, low power, configurable systems, system-on-a-chip, platforms, architecture tuning.