Specifications
Table Of Contents
- 1 Overview and Key Features
- 2 Specification
- 3 Hardware Specifications
- 4 Power Consumption
- 5 Functional Description
- 5.1 Power Management
- 5.2 BL654 Power Supply Options
- 5.3 Clocks and Timers
- 5.4 Radio Frequency (RF)
- 5.5 NFC
- 5.6 UART Interface
- 5.7 USB interface
- 5.8 SPI Bus
- 5.9 I2C Interface
- 5.10 General Purpose I/O, ADC, PWM and FREQ
- 5.11 nRESET pin
- 5.12 Two-Wire Interface JTAG
- 5.13 BL654 Wakeup
- 5.14 Low Power Modes
- 5.15 Temperature Sensor
- 5.16 Security/Privacy
- 5.17 Optional External 32.768 kHz crystal
- 5.18 451-00001 On-board PCB Antenna Characteristics
- 5.19 451-00003 USB BLE 5.1 Dongle Mechanical Details
- 6 Hardware Integration Suggestions
- 7 Mechanical Details
- 8 Application Note for Surface Mount Modules
- 9 Regulatory
- 10 Ordering Information
- 11 Bluetooth SIG Qualification
- 12 Additional Assistance
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modules/bluetooth-modules/bluetooth-5-
modules/bl654-series-bluetooth-module-nfc
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The BL654 supports readback protection capability that disallows the reading of the memory on the nrf52840 using a JTAG
interface. Available via smartBASIC or the Nordic SDK.
The BL654 offers a range of functions for generating public/private keypair, calculating a shared secret, as well as generating an
authenticated hash. Available via smartBASIC or the Nordic SDK.
This is not required for normal BL654 module operation.
The BL654 uses the on-chip 32.76 kHz RC oscillator (LFCLK) by default (which has an accuracy of ±500 ppm) which requires
regulator calibration (every eight seconds) to within ±500 ppm.
You can connect an optional external high accuracy (±20 ppm) 32.768 kHz crystal (and associated load capacitors) to the
BL654SIO_01/XL2 (pin 41) and SIO_00/XL1 (pin 42) to provide improved protocol timing and to help with radio power
consumption in the system standby doze/deep sleep modes by reducing the time that the RX window needs to be open. Table
23 compares the current consumption difference between RC and crystal oscillator.
Table 23: Comparing current consumption difference between BL654 on-chip RC 32.76 kHz oscillator and optional
external crystal (32.768kHz) based oscillator
BL654 On-chip 32.768 kHz RC Oscillator
(±500 ppm) LFRC
Optional External Higher Accuracy (±20
ppm) 32.768 kHz Crystal-based Oscillator
LFXO
Current Consumption
of 32.768 kHz Block
0.7 uA
0.23 uA
Standby Doze Current
(SYSTEM ON IDLE +full
RAM retention +RTC
run current + LFRC or
LFXO)
3.1 uA
2.6 uA
Calibration
Calibration required regularly (default eight
seconds interval).
Calibration takes 33 ms; with DCDC used, the
total charge of a calibration event is 16 uC.
The average current consumed by the
calibration depends on the calibration interval
and can be calculated using the following
formula:
CAL_charge/CAL_interval – The lowest
calibration interval (0.25 seconds) provides an
average current of (DCDC enabled):
16uC/0.25s = 64uA
To get the 500-ppm accuracy, the BLE stack
specification states that a calibration interval of
eight seconds is enough. This gives an
average current of:
16uC/8s = 2 uA
Added to the LFRC run current and Standby
Doze (IDLE) base current shown above results
Not applicable