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Video: An Overview of the Differences between the Nordic nRF51 and nRF52

Stephanie Guimera in Blogs on August 07, 2015

About Stephanie Guimera

The Nordic nRF51-DK and nRF52 Preview DK are versatile development boards for Bluetooth® Smart, ANT, or 2.4GHz proprietary applications. The nRF52 introduces a number of new features and peripherals, bolstered by the addition of a Cortex M4F processor, which has been implemented with full debug and trace support.


Differences between the Nordic nRF51 and nRF5

Frequency band
2.4GHz ISM ( 2.40000 –2.4835GHz)
Frequency band
2.4GHz ISM (2.36000 –2.4835GHz)
On-air data rate
250 kbps, 1 Mbps or 2 Mbps
On-air data rate
1 Mbps or 2 Mbps

51822 : -93dBm for Bluetooth smart (-96dBm at 250kb -90dBm at 1Mbs -85dBm at 2Mbs)

51422 : -93dBm for Bluetooth smart, -90dBm ANT, -85dBm at 2Mbs, -30dBm whisper mode

-96dBm for Bluetooth smart, -92.5dBm at 1Mbs ANT, -89dBm at 2Mbs, -30dBm whisper mode
Radio current consumption LDO at 1.8V

-16mA –TX at +4dBM output power

-10.5mA –TX at 0dBm output power

-13mA –RX at 1Mbs

Radio current consumption LDO at 1.8V

-15.2mA –TX at +4dBM output power,

-10mA –TX at 0dBm output power,

-10.4mA –RX at 1Mbs

32-bit ARM Cortex M0
32-bit ARM Cortex M4F 
Program memory
256/128 KB Flash(40kB-180kB available for application development)
Program memory
512kB Flash (400 kB available for application development)
-16MHz crystal oscillator

-16MHz RC oscillator

-32kHz crystal oscillator

-32kHz RC oscillator (±250 ppm)


-32MHz crystal oscillator,

-64MHz RC oscillator,

-32kHz crystal oscillator,

-32kHz RC oscillator (±250 ppm)

16-channel PPI
Voltage regulator

LDO (1.8 to 3.6V),

LDO bypass (1.75 to 1.95V)

Buck DC/DC (2.1 to 3.6V)

Voltage regulator

-LDO (1.7 to 3.6V),

-Buck DC/DC (1.7 to 3.6V)

31 configurable
32 configurable
10-bit ADC, RNG, Temperature sensor, RTC
12-bit/200KSPS ADC, RNG, Temperature sensor
2 x 16 bit, 1 x 24bit, 2 x 24bit, RTC
5 x 32bit, 3 x 24bit RTC

New Features of the nRF52

  • General purpose comparator
  • Event Generator Unit (EGU)
  • A 2 kB direct mapped cache


Features Removed

  • UICR configuration options in the nRF52 Series:
    • RBPCONF - Replaced by APPROTECT
    • CLENR0 - Because the nRF51 style MPU is removed, this has been removed as well
    • XTALFREQ - 32 MHz crystal support only
    • FWID - Uses generic NRFFW registers
    • FICR configuration options in the nRF52 Series:
      • CLENR0 - Because the MPU has been removed, this has been removed as well
      • PPFC - Replaced by APPROTECT in UICR
      • OVERRIDEEN - Not needed
      • NRF_1MBIT[x] - Not needed
      • BLE_1MBIT[x] - Not needed


New Peripherals

  • Near Field Communication Tag (NFCT)
  • Pulse Density Modulation (PDM)
  • Inter-IC Sound (I2S)
  • Memory Watch Unit (MWU)
  • Pulse Width Modulation (PWM)


Additions and Improvements

  • The radio now offers TXPOWER modes configurable from +4 dBm to -40 dBm, support for Bluetooth Low Energy packet length extension, and Fast radio ramp-up time (40 µs)
  • An additional UART peripheral has been added
  • An additional RTC instance has been added
  • The ADC peripheral is replaced by a differential Successive Approximation Register Analog to Digital Converter (SAADC). The interface supports up to 4 differential inputs and EasyDMA for CPU offloading
  • All timers now support all bit modes (8, 16, 24, and 32 bits)
  • Set and Clear tasks have been added, and the number of tasks/events increased from 4 to 8
  • The number of PPI groups has increased from 4 to 6. A new type of endpoint called FORK can be used to trigger an additional task from a single event endpoint
  • New UICR configuration options in the nRF52 Series:
    • PSELRESET - Programmable reset pin that can be multiplexed to either GPIO or RESET
    • APPROTECT - Read-back protection mechanism



The nRF51 is still a solid option, especially for existing developments in which timing is crucial.


For more information about the nRF51, nRF52, and the associated development kits, call Symmetry at (310) 536-6190 or contact us online



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