ARM Cordio BT4 Radio IP, User Manual, Page: 25 / 36

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6 TEST MODE
The Test Mode (also known as “HCI Pass-through” mode) allows control of the BT4 Radio IP block via the BT4
Host MCU’s UART port (J14). This allows external test devices and radio control programs (RCT) to talk directly to
the Radio IP via HCI commands such as Directed Test Mode (DTM) commands per the Bluetooth specification.
This is useful in RF evaluation as well as regulatory approval tests.
The following board configuration is required:

The board must be powered via 5 volts (USB cable) to be able to use the Host UART port.

The UART Jumper headers (J8 & J9) must be in the Header position (See Section 3.3.4).

The FW mode must be set to “HCI FW” (See Section 4).

The UART speed is 115200 baud, 8 bit, 1 stop, no flow control
Please note that the UART supports 3.3 volt signal level. A USB to UART cable is provided in the Kit that
supports 3.3 volt signal level. If you are connecting the Eval board to the RS-232 port of test equipment such
as a Bluetooth Analyzer, you will need to install a signal level shifting cable or adapter! RS-232 to 3.3V
TTL cables similar to these links can be obtained: http://techref.massmind.org/techref/io/serial/RCL1.htm or
http://www.digikey.com/product-search/en/programmers-development-
systems/accessories/2621524?k=MAX3232
Some bench top test equipment require an Access Address to be enterered to enable it to communicate to BLE
devices via DTM commands (Direct Test Mode). The correct Access Address is 71764129.
6.1 Radio Control and RF Evaluation
Control of the radio for RF evaluations can be performed in a variety of methods and test configurations.
6.1.1 Use of Bluetooth Analyzer/Testers
Bluetooth Radio Analyzer that can control the Device Under Test (DUT) or EUT via DTM commands over UART
(3.3v signaling) can talk to the BT4 Radio IP via J14 (See Section 3.4.1).
The most commonly used test equipment to complete this task is either the Rohde & Schwarz CBT32 or CMW
500. Similar test equipment is provided by other vendors as well such as Anritzu or TESCOM.
The common test set-up is depicted in the figure below. The DUT/EUT is controlled via the UART interface while
RF measurements are received via a calibrated RF Coax cable, typically with an in-line 10db attenuator.
Figure 6.1.1
– Bluetooth Analyzer Set-up