The BlueNRG low-power Bluetooth Low Energy network processor IC from StMicroelectronics is compliant with the v4.0 specification. Bluetooth seems to be coming into great favor now, partly due to the Low Energy specification along with the fact that several suppliers are now making single-chip devices that can replace modules and be much more cost effective.
This STMicroelectronics implementation looks to be the best around, with the lowest power draw (just 7.3 mA active receive peak current) and excellent transmit/receive specs. It can act as master or slave and the Bluetooth LE stack runs on its Cortex M0 core while flash memory allows in-field upgrading.
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