Laird BL654 User Manual page 17

Table 3 displays the four signals running from Atmel MCU U14 (SWD interface plus SIO_32 and nReset_BLE) to the BL654
module (SWD interface plus SIO_32 and nReset_BLE).
Table 3: USB U4 USB-SWD to BL654 SWD signal routing connections
U4 (Atmel MCU) Net
SWD Interface into
Analog switch U24
OB_SWDCLK
OB_SWDIO
OB_RESET
OB_SWO
SIO_32 is a trace output (called SWO, Serial Wire Output) and is not necessary for programming BL654 over the SWD
interface.
nReset_BLE is not necessary for programming BL654 over the SWD interface.
The development board provides access to the BL654 module four-wire UART interface (TX, RX, CTS, RTS) either through
USB (via UT10 FTDI USB-UART convertor chip) or through a breakout header connector J1.
Note: The BL654 module provides four-wire UART interface on the HW and the other four signals (DTR, DSR, DCD, RI),
which are low bandwidth signals, can be implemented in a smartBASIC application using any spare digital SIO
pins.
The UART connection on the BL654 series module and the FTDI IC are shown in
series module UART is mapped to the breakout header connector J1. These connections are listed in
Table 4: SIO/UART connections
BL654 (U5) SIO BL654 Default Function
SIO_06 (U5 pin35) UART_TX (output)
SIO_08 (U5 pin29) UART_RX (input)
SIO_05 (U5 pin39) UART_RTS (output)
SIO_07 (U5 pin37) UART_CTS (input)
Note: Additionally, SIO_35 (the nAutoRUN input pin on the module) can be driven by the USB_DTR output pin of the
FTDI chip. This allows testing the $autorun$ application on boot without setting the autorun jumper on the
development board. nAutorun can be controlled directly from Laird's UWTerminalX using the DTR tick box.
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USB cable plugged into USB2
(USB_DETECTp HIGH)
Route SWD Interface from Atmel
MCU (U4) to BL654 Module
Net Name
SWDCLK_BLE (pin 3)
SWDIO_BLE (pin 1)
nRESET_BLE (pin 19)
via R131 0R (Not populated)
SIO_32 (pin 7)
FTDI IC UART
USB_RX
USB_TX
USB_CTS
USB_RTS
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No USB cable plugged into USB2
(USB_DETECTp LOW)
Route SWD Interface from Atmel MCU
(U4) to JP1
SWDCLK_EXT (JP1 pin4)
SWDIO_EXT (JP1 pin2)
nRESET_EXT (JP1 pin10)
SWO_EXT (JP1 pin6)
via SB21 open solderbridge
Table 4. Figure 10
17
Comments
explains how the BL654
Table 4.
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