nRF52832 VS nRF52840: Choosing the Right Bluetooth Workhorse
Silicon at a Glance
The nRF52832 arrived in 2016 with a 64 MHz Cortex-M4 and 512 kB of flash, while the nRF52840 landed a year later boasting a 64 MHz Cortex-M4F, 1 MB of flash, and a bigger radio engine. Both ship as pre-certified modules, but the 840’s extra memory and security blocks make it the go-to for edge-heavy applications, whereas the 832 remains the darling of cost-sensitive wearables and toys.
Radio Reach: +4 dBm vs. +8 dBm
The 832 tops out at +4 dBm transmit power; the 840 pushes +8 dBm and drops to −96 dBm receive sensitivity. In open air that translates to 60 m vs. 120 m line-of-sight—handy for agricultural sensors that must hop across irrigation ditches without extra front-end chips.
Memory Map: 512 kB vs. 1 MB
Twice the flash means twice the room for over-the-air updates and on-device ML models. A 832-based fitness tracker might store seven days of heart-rate data; a 840 smart-lock can cache six months of audit logs and still have space for a second firmware bank.
Security Armoury
The 840 adds hardware AES-256, SHA-256, ECC, and ARM TrustZone-M; the 832 relies on software crypto. For medical devices that must sign sensor data, the 840 trims calculation time from 90 ms to 9 ms and cuts power by 80 %.
Power Budget: Micro-amps in Deep Sleep
Both sip 0.3 µA with RAM retained, but the 840’s DC-DC converter automatically bypasses under heavy load, trimming 15 % from peak transmit current. A 832 step-counter lasts five years on a CR2032; a 840 door-lock with the same battery survives eight, despite the bigger radio.
Peripheral Parade
Both offer SPI, I²C, UART, ADC, and PWM, but the 840 adds USB 2.0 full-speed and QSPI for external flash. The 832 suffices for step-counters; the 840 drives 320 × 320 TFT displays without external driver chips.
Real-World Scenarios
A 832 module rides inside $30 fitness bands, broadcasting heart-rate every second for five years. The same silicon tags supermarket trolleys, using +4 dBm to reach a ceiling gateway 30 m away.
A 840 module powers $80 smart-locks, storing six months of audit logs and using +8 dBm to cross 120 m of car-park. The same chip drives a Zigbee/Thread border router, juggling BLE and 802.15.4 stacks simultaneously.
Roadmap Reality
Both chips support Bluetooth 5.0 long-range and 2 Mbps high-speed, but only the 840 has hardware-qualified for Bluetooth 6.0 channel-sounding—a firmware update will unlock centimetre-level distance measurement. If your product roadmap ends at “accurate enough,” pick the 832; if it ends at “radar-accurate,” budget for the 840.
Conclusion: Horses for Courses
Choose the nRF52832 when cost, size, and five-year battery life trump fancy crypto or long range. Pick the nRF52840 when you need a radio that doubles as a micro-server, stores months of data, and still sips power. Both are proven workhorses—one is a sprinter, the other a marathon runner with a backpack.