www.lairdtech.com/bluetooth
19
© Copyright 2018 Laird. All Rights Reserved
Americas: +1-800-492-2320
Europe: +44-1628-858-940
Hong Kong: +852 2923 0610
If the BL654 on the development board is powered from 1.8V supply, then you must use the 1.8V version of the FTDI USB-
UART cable. UART signal levels always need to match the supply voltage net VDD_nRF_SW of the BL654 development
board.
Figure 11: J1 wiring to match FTDI USB-UART cable (TTL-232R-3V3 cable)
Fit a jumper in J35 (to switch the Analog switch U15 and route BL654 UART to J1) when connecting an external FTDI USB-
UART TTL (3.3V) converter cable using J1.
Fitting a jumper in J35 also allows the BL654 UART to be routed to Atmel MCU UART (signal also on J19 and net names
beginning with IMCU_) via open solder bridges SB16 to SB19 shown in
Figure 12
. You must connect these bridges with
solder. This may be useful for those customers wanting to work with the Nordic SDK.
Figure 12: Open solder-bridges on the UART interface running from Atmel MCU (U4) to analog switch U15 (to BL654 ultimately)
On the development board, the USB_DTR output (FTDI chip U10) from the PC is wired to BL654 module pin SIO_35 (pin 5)
which is the nAutoRUN pin.
Note:
smart
BASIC runtime engine FW checks for the status of nAutoRUN during power-up or reset. The nAutoRUN pin
detects if the BL654 module should power up into Interactive/Development Mode (3.3 V) or Self-contained Run
mode (0V). The module enters Self-contained Run mode if the nAutoRUN pin is at 0V and an application called
$autorun$ exists in the module
’
s file system, then the
smart
BASIC runtime engine FW executes the
smart
BASIC
application script automatically; hence the name Self-contained Run mode.
SIO_06
R1
NOPOP (0R)
Module pin BL654 UART Data Flow
SIO_06 Module_TX Output
SIO_08 Module_RX Input
SIO_05 Module_RTS Output
SIO_07 Module_CTS Input
SIO_07
SIO_08
VDD_VSRC_nRF
SIO_05
FTDI (USB to TTL 232 Cable)
GND
USB_CTS
VCC
USB_TX
USB_RX
USB_RTS
GND
RTS
VCC
RX
TX
CTS
J1
NOPOP (PIN HEADER,2.54mm 1X6P)
1
1
2
2
3
3
4
4
5
5
6
6
GND
IMCU_RTS_A
IMCU_RxD_A
SB19
NOPOP (Solderbridge_Open)
1
1
2
2
IMCU_TxD_A
IMCU_RTS
IMCU_CTS
IMCU_TxD
IMCU_RxD
SB16
NOPOP (Solderbridge_Open)
1
1
2
2
IMCU_CTS_A
SB17
NOPOP (Solderbridge_Open)
1
1
2
2
SB18
NOPOP (Solderbridge_Open)
1
1
2
2
Summary of Contents for BL654
Page 1: ...Version 1 1 ...
