What this BLE system-on-chip brings to the board
The Texas Instruments CC2540F256RHAT is a Bluetooth v5.0-compliant single-chip solution that integrates a 2.4 GHz transceiver with an 8051-based MCU core. The receiver hits -93 dBm sensitivity, and the transmitter can deliver up to 4 dBm output power. With 21 GPIOs and serial interfaces including SPI, USART, and USB, this part handles sensor aggregation, data logging, and peripheral control on a single die.
Memory and I/O budget for BLE firmware
256 kB of Flash is the program store — enough for the Bluetooth stack, a custom profile, and a modest application. The 8 kB SRAM is the tight spot: it holds the stack's heap, GATT database, and any data buffers. If your design streams sensor data or keeps multiple connections open, you will need to budget the SRAM carefully. The 21 GPIOs are multiplexed with the serial interfaces, so a design using SPI, USART, and USB simultaneously will consume several of those pins. Plan the pin allocation early.
Power draw and thermal reality
Receive current runs between 19.6 mA and 22.1 mA; transmit current ranges from 21.1 mA to 31.6 mA depending on output power and supply voltage. The 40-VFQFN Exposed Pad package relies on the PCB copper to sink heat — if you are running continuous TX at 4 dBm near the 3.6 V supply rail, the junction temperature climbs.