Laird BL654 Installation and operating instructions

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Application Note v1.2
The BL654 firmware natively supports Direct Test Mode (DTM) commands as specified in the Bluetooth SIG’s Bluetooth Core
Specifications v 5.0 vol. 6 part F - Direct Test Mode, accessible from the following link:
www.bluetooth.com/specifications/bluetooth-core-specification
The purpose of DTM is to test the operation of radio at the physical layers such as for transmit power and receiver
sensitivity. This is useful for regulatory EMC testing or for co-located radio testing with another radio system.
This radio test can be carried out by dedicated test equipment (such as Anritsu MT8852 or similar) with the BL654 in DTM
mode as the device under test. Alternatively, you can send DTM commands from a PC using a terminal program such as
UwTerminalX. In both cases, the DTM commands remain the same.
This document describes BL654 radio testing using the in-built Direct Test Mode (DTM) firmware and Nordic’s nRFgo Studio
or Laird Connectivity BleDtmRfTool.
▪Entering DTM mode for the BL654
▪Using Nordic nRFgoStudio DTM panel (or Laird BleDtmRfTool) to BLE radio test BL654 in either Transmit or Receive
mode.
▪Exiting DTM mode for the BL654
To use DTM, you need the following:
▪DVK-BL654-1.0 development board
▪Windows PC
▪UwTerminalX by Laird Connectivity (available at https://github.com/LairdCP/UwTerminalX/releases)
▪Laird Connectivity BleDtmRfTool –This is available from the Documentation section of the BL654 product page.
Note: You must be logged into your Laird Connectivity account for the BleDtmRfTool to work.
▪Nordic nRFgoStudio application software (the complete install found on the Downloads panel at the following link:
http://www.nordicsemi.com/eng/Products/Bluetooth-low-energy/nRF52832
Note: Please install the correct version (32- or 64-bit) for your operating system.
Code
Name
Version
nRFgo Studio-Win32
Software tool for nRFgo Starter Kit and Development Kits for 32-bit (x86) Windows
XP, Windows Vista, Windows 7, and Windows 8
1.21.2
nRFgo Studio-Win64
Software tool for nRFgo Starter Kit and Development Kits for 64-bit (x64) Windows
Vista, Windows 7, and Windows 8
1.21.2

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We assume the DVK-BL654-1.0 development kit has its default out-of-the-box settings as described in the BL654 Quick Start
Guide (available from the BL654 product page https://www.lairdconnect.com/wireless-modules/bluetooth-
modules/bluetooth-5-modules/bl654-series-bluetooth-module-nfc). In this mode, it is in AT or interactive mode (no
smartBASIC application loaded or running) on power up.
Figure 1: J12 fitted over pins 1 and 2, and SW3 (reset button)

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To enter DTM, follow these steps:
Open UwTerminalX.
Ensure you’re using the latest version of UwTerminalX by clicking the Update tab and then, in the UwTerminalX
panel, click Check for Updates.
When you’re running the newest version of UwTerminalX, open the Config tab.
In the device drop down, select BL654 to populate the default communications settings.
Select the correct COM port.
If you cannot select BL654, manually select the following UART settings (shown in Figure 2):
COM Port
Port corresponding to your development kit
Baud Rate
115200
Parity
None
Stop Bits
1
Data Bits
8
Handshaking
CTS/RTS
Figure 2: UwTerminalX Settings
Click OK to connect.

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Set up the module into Direct Test Mode, you will need to retrieve two sets of four characters each which function as
a unique passcode to enter direct test mode. To retrieve the characters, issue the following command:
AT I 14
You should receive a response such as:
10 14 01 123456789ABC
Note the characters in the highlighted positions above. In our example in Figure 3, they are CB71 and 7B03.
Figure 3: Return from at i 14
To enter Direct Test Mode, using the characters you found in the previous steps, issue the AT+DTM command as
follows:
AT+DTM 0xCB717B03
The module is now in Direct Test mode.
Click Close Port to disconnect the development board from UwTerminalX.

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Now that the module is in Direct Test Mode, it accepts DTM commands as specified in the BT SIG Bluetooth Core
Specifications. See Bluetooth Core Specifications v 4.1 vol. 6 part F - Direct Test Mode, at
https://www.bluetooth.com/specifications/bluetooth-core-specification.
To use Direct Test Mode, you need Nordic’s nRFgo Studio, found at: http://www.nordicsemi.com/eng/Products/Bluetooth-
low-energy/nRF52832
Once the BL654 is in DTM mode, you can communicate with the BL654 over the UART with UwTerminal using the following
communications settings:
COM Port
Same as before
Baud Rate
19200
Parity
None
Stop Bits
1
Data Bits
8
Handshaking
CTS/RTS
Before entering DTM Mode, you may configure TX Power, Baud Rate, and DCDC. Changing these values is optional.
However, if you choose, you may set these values as follows (Note that if using BL654 firmware 29.5.7.2 and an option is
changed, the following command must be used prior to entering DTM mode to allow the radio to operate: AT+DTMCFG 19
1):
Command
AT+DTMCFG 1 n
Values for n
8, 7, 6, 5, 4, 3, 2, 0, -4, -8, -12, -16, -20, -40
Default
8
Command
AT+DTMCFG 2 n
Values for n
9600, 14400, 19200, 38400, 57600, 115200
Default
19200
Command
AT+DTMCFG 3 n
Values for n
0 (Disabled), 1 (enabled)
Default
1

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Command
AT+DTMCFG 11 n
Values for n
0 (Disabled), 1 (enabled)
Default
0
Command
AT+DTMCFG 4 n
Values for n
0 (Disabled), 1 (enabled)
Default
1
Command
AT+DTMCFG 5 n
Values for n
0 (Disabled), 1 (enabled)
Default
0
This will be ignored if AT+DTMCFG 5 is set to 0 (which is the default). If a bit is set then the bit number corresponds to the
GPIO number which is enabled.
Command
AT+DTMCFG 6 bitmask
Values for n
0x00000000 to 0xFFFFFFFF (bit 0 is the lowest significant bit)
Default
0
This will be ignored if AT+DTMCFG 5 is set to 0 (which is the default). If a bit is set then the bit number corresponds to the
GPIO number will have the direction input when the bit is 0 and an output when the bit is 1.
Command
AT+DTMCFG 7 bitmask
Values for n
0x00000000 to 0xFFFFFFFF (bit 0 is the lowest significant bit)
Default
0
This will be ignored if AT+DTMCFG 5 is set to 0 (which is the default). If a bit is set then the bit number corresponds to the
GPIO number will have the output set to this value if DTMCFG 7 was used to set the direction as output.
Command
AT+DTMCFG 8 bitmask
Values for n
0x00000000 to 0xFFFFFFFF (bit 0 is the lowest significant bit)
Default
0xFFFFFFFF

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This will be ignored if AT+DTMCFG 5 is set to 0 (which is the default). If a bit is set then the bit number corresponds to the
GPIO number which is enabled.
Command
AT+DTMCFG 16 bitmask
Values for n
0x0000 to 0xFFFF (bit 0 is the lowest significant bit)
Default
0
This will be ignored if AT+DTMCFG 5 is set to 0 (which is the default). If a bit is set then the bit number corresponds to the
GPIO number will have the direction input when the bit is 0 and an output when the bit is 1.
Command
AT+DTMCFG 17 bitmask
Values for n
0x0000 to 0xFFFF (bit 0 is the lowest significant bit)
Default
0
This will be ignored if AT+DTMCFG 5 is set to 0 (which is the default). If a bit is set then the bit number corresponds to the
GPIO number will have the output set to this value if DTMCFG 7 was used to set the direction as output.
Command
AT+DTMCFG 18 bitmask
Values for n
0x0000 to 0xFFFF (bit 0 is the lowest significant bit)
Default
0xFFFFFFFF

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nRFgoStudio does not allow the data rate to be changed and default is 1Mbps, other PHY data rates such as 2Mbps, coded
PHY 500kbps (s=2) and 125kbps (s=8) cannot be selected.
To begin using Direct Test Mode, follow these steps:
Open Nordic nRFgo Studio.
In nRFgo Studio, click Direct Test Mode in the features panel to open the Direct Test Mode panel as shown in
Figure 4.
Figure 4: Opening the Direct Test Mode panel
From there, you can place the module in constant TX or RX mode. Consult the nRFgo Studio built-in help for more
information.
To conduct a transmit test, configure the options in the Direct Test Mode panel as follows:
COM Port
Same as previous
Mode
Transmit
Channel
19 (2440 MHz)
Payload Model
PRBS9 –If a BLE-modulated TX signal is required
-or-
Constant Carrier –If a continuous [CW] TX signal is required
Payload Length
37 bytes
Once configured, click Start Test. If successful, no errors should show, as illustrated in Figure 5.

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Figure 5: Successful initiation of TX Test
With the module is in a Transmit test, you can measure the signal on a spectrum analyzer.
To conduct a receive test, configure the options in the Direct Test Mode panel as follows:
COM Port
Same as previous
Mode
Receive
Channel
0 (2402 MHz)
Once configured, click Start Test. If successful, no errors should show.
Note: Rx Mode produces an RX LO leakage at the following frequency: 2*fRx-1MHz.

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Laird Connectivity’s BleDtmRfTool allows all BT PHY data rates to be tested, 1 Mbps, 2 Mbps and coded PHY 500 kbps (s=2)
and 125 kbps (s=8).
To begin using Direct Test Mode, follow these steps:
Open Laird Connectivity BleDtmRfTool (Figure 6).
Figure 6: BleDtmRfTool UART communication settings
In BleDtmRfTool, click DTM button located in the top right to open the Direct Test Mode panel as shown in
Figure 7.
Figure 7: BleDtmRfTool

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In BleDtmRfTool DTM panel, there are two ways to use BleDtmRfTool, either manual entry or pressing buttons
(Figure 8).
Figure 8: Opening the Direct Test Mode panel in BleDtmRfTool
Manual entry
Pressing buttons

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To perform a transmit test, follow these steps:
Always start by pressing LE RESET.
Configure the applicable options in the Direct Test Mode. See Figure 9 for an example.
Figure 9: Direct Test Mode options
COM Port
Same as previous
LE RESET
First start by pressing LE RESET.
Data rate
Select data rate from 1 MPHY or 2 MPHY or LE CODED (S=8) or LE CODED (S=2) or selecting
continuous CW select 1 MPHY
Standard or
Stable
Modulation
Index
BL654 series BLE module currently does support standard modulation index, so press MOD’N
INDEX (STD)
Channel
19 (2440 MHz)
Payload Model
i.e. Pkt Type
Pkt Type Value Parameter Description
00 PRBS9 Packet Payload
01 11110000 Packet Payload
10 10101010 Packet Payload
11 on the LE Uncoded PHYs: Vendor Specific
on the LE Coded PHY: 11111111
Pkt Type 00 –If a BLE-modulated TX signal is required with PRBS9 Packet payload
-or-
Pkt Type is 11 –If a continuous [CW] TX signal is required

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Payload Length
0 bytes to 63 bytes
Set Length to 0 –If a continuous [CW] TX signal is required
TRANSMIT
To start TX test press TRANSMIT
Once configured, click TRANSMIT. If successful, no errors should show, as illustrated in Figure 5.Figure 8 shows a TX
CW test.
Figure 8: Successful initiation of TX Test
With the module is in a Transmit test, you can measure the signal on a spectrum analyzer.
To conduct a receive test, configure the options in the Direct Test Mode panel as follows:
COM Port
Same as previous
LE RESET
First start by pressing “LE RESET”.
Data rate
1MPHY or 2MPHY or LE CODED (S=8) or LE CODED (S=2)
Standard or Stable
Modulation Index
BL654 series BLE module currently does support standard modulation index, so
press MOD’N INDEX (STD)
Channel (fRx)
19 (2440 MHz)
Payload Model
(such as Pkt Type)
Pkt Type Value
Parameter Description
00
PRBS9 packet payload
01
11110000 packet payload
10
10101010 packet payload
11
On the LE Uncoded PHYs –Vendor Specific
On the LE Coded PHY –11111111
Pkt Type 00 –If a BLE-modulated RX signal is required with PRBS9 Packet payload

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Payload Length
0 bytes to 63 bytes
Set Length to 0 –If a continuous [CW] TX signal is required
RECEIVE
To start RX test press RECEIVE
Once configured, click RECEIVE. If successful, no errors should show. The RX Event shows how many packets are received.
Note: Rx Mode produces an RX LO leakage at the following frequency: 2*fRx-1MHz.
To exit DTM, follow these steps:
Open UwTerminalX with the following settings:
COM Port
Same as previous
Baud Rate
19200
Parity
None
Stop Bits
1
Data Bits
8
Handshaking
None
Click OK to connect.
Right-click the terminal screen and in the context menu, click Automation.
In the following screen, modify the fields as shown in Figure 10.
▪In the first field, enter \3F\FF
▪In the second field, enter \3F\FE (Note: this command is applicable to BL654 firmware version 29.5.7.2 onwards
only).
▪Tick the box for De-Escape Strings.
To clear DTM configuration and exit from it until the DTM command is used again, click the second use button, to
exit temporally until the module is reset or power cycled, press the first send button
Figure 10: Automation dialogue
After this command is complete, close UwTerminalX. Then re-open it and connect to the BL654 with the following
default parameters:

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COM Port
Same as previous
Baud Rate
115200
Parity
None
Stop Bits
1
Data Bits
8
Handshaking
CTS/RTS
Click OK to connect.
Check that you get a response by pressing Enter in the terminal window. You should the following response:
00
If you wish to change any DTM configuration, you may do so now, you can also query what the current DTM
configuration is by using the “at+dtmcfg X?” where X is the index to query, as specified in the Configuration of
Module Settings (Optional) section.
If you would like to erase all non-volatile data and the module’s file system, enter this command:
at&f*
The module erases its file system and reboot, as shown in Figure 11.
Figure 11: at&f* to erase and reboot module
Version
Date
Notes
Contributor(s)
Approver
1.0
25 June 2018
Initial Release
Raj Khatri
Jonathan Kaye
1.1
2 Oct 2019
Updated with new DTMCFG keys
Mahendra Tailor
1.2
18 Jan 2021
Updated with DCDC REG0, clear DTM
config and firmware 29.5.7.2 workaround
Jamie Mccrae
Jonathan Kaye