Project #018: Direct Test Mode (DTM) | Cypress Semiconductor
Project #018: Direct Test Mode (DTM)
In today's project, we will learn about Bluetooth Low Energy's Direct Test Mode (DTM).
DTM is a standard mode in the BLE 4.1 specification (Vol 6, Part F) that allows testing of the radio's Physical Layer (PHY) by transmitting and receiving sequences of test packets. This is often used in compliance and production-line testing, without the need of going through the complete BLE Protocol Stack, i.e. it skips the Host Stack and talks directly to the radio in an isolated manner.
Another layer in the BLE specification is the Host Controller Interface (HCI) - a standard-defined interface to exchange data between the BLE Host Stack and the radio Controller. In PSoC 4 BLE, the underlying physical communication for the HCI protocol is UART. Through UART, the commands and responses are communicated between the PSoC 4 BLE and a commercial RF Tester. When the HCI mode is selected in the BLE Component, a UART Component in PSoC 4 BLE is reserved for this use. Once the BLE Component is configured for HCI mode, there is no further application code to be written to implement the DTM mode, except enabling global interrupts, starting the BLE Component, and processing BLE events. The proper response to commands from tester is handled by the BLE Stack as part of BLE Component.
Several commercial options are avaialble for RF Testers. In this example, we use the Rohde&Schwarz CBT Tester.
You can download this PSoC Creator project along with a detailed PDF of instructions, here from GitHub: https://github.com/cypresssemiconductorco/PSoC-4-BLE/tree/master/100_Projects_in_100_Days/Day018_Direct_Test_Mode