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BL654 Pin (Pin Name)
U18 Pin (QSPI flash IC)
and Pin Name
Via Open Solder bridge
Pin 12 (SIO_21/QSPI_DIO1)
Pin 2 SIO_1/SO
SB6
Pin 11 (SIO_22/QSPI_DIO2)
Pin 3 SIO_2/WP#
SB11
Pin 9 (SIO_23/QSPI_DIO3)
Pin 7 SIO_3/HOLD#
SB10
The
smart
BASIC application for this external optional serial QSPI flash IC will be available in the future in the GitHub
smart
BASIC sample application repository:
https://github.com/LairdCP/BL654-Applications
The BL654 on-chip 32.768kHz RC oscillator provides the standard accuracy of ±250 ppm, with calibration required every 8
seconds (default) to stay within ±250 ppm.
The BL654 also allows, as an option, to connect an external higher accuracy (±20 ppm) 32.768 kHz crystal to the BL654-SX-
xx pins SIO_01/XL2 (pin 41) and SIO_00/XL1 (pin 42). This provides improved protocol timing and helps with radio power
consumption in the system standby doze/deep sleep modes by reducing the time that the Rx window must be open.
To connect the optional external 32.76kHz crystal oscillator circuit to the BL654 module, remove R127 and R128 and short
SB8 and short SB9.
Figure 20: Optional external 32.768kHz crystal circuit schematic and PCB
A
smart
BASIC application will be available in the future in the GitHub
smart
BASIC sample application repository at:
https://github.com/LairdCP/BL654-Applications
.
GND
R127
0R
R128
0R
SIO_00_Header
GND
Y 3
32.768KHz,20ppm,9pF
1
2
SIO_00
XL1
SIO_01
C70
10pF,50V
C71
12pF, 50V
XL2
SIO_01_Header
SB8 NOPOP (Solderbridge_Open)
1
1
2
2
SB9 NOPOP (Solderbridge_Open)
1
1
2
2
NOPOP (PIN HEADER,2.54mm 1X2P)
J44
1
1
2
2
SIO_00_Header
SIO_01_Header
Summary of Contents for BL654
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