BT LE RN4020 USB Dongle Datasheet

Transcription

1 BT LE RN4020 USB Dongle Datasheet Introduction BT LE RN4020 Dongle is a USB Stick type device build around Microchip s RN4020 module which provides a fully command based interface to manage the module. The RN4020 module is a Bluetooth Low Energy compatible device and supports Bluetooth Core Specification v4.1. More information about RN4020 can be found on Microchip s webpage. The dongle is designated to work without a need of any additional equipment like oscilloscope or logic analyser thus it can be used especially by software engineers not familiar with electronics equipment. To work with the dongle the user needs any host computer which supports Standard COM Port Interface. This includes PC computers with operating systems supporting COM Port like for example Windows, Linux or MAC OS. Additionally other embedded systems can be used as a host computer including Raspberry Pi. The module can be managed by a standard terminal application which can stream data to COM Port or the user can develop his own software to work with the Dongle using any technology which supports COM Port, like for example Java, C# or Python. The USB COM Port Interface provided by the module is made using FTDI FT234XD chip. This device is widely supported by various operating systems and libraries or can be downloaded from the FTDI website. Module diagram 1 P a g e

2 Diagram 1 provides information about internal connections in the BT LE RN4020 USB Dongle device. The microcontroller inside the device manages the whole connection between the host computer and the RN4020 module. It provides to the user an easy to use command interface to help with controlling / reading IO line states and transmitting / receiving data through the UART. Diagram 1 COM PORT Configuration The FTDI FT234XD IC provides a standard USB COM Port interface which is widely supported by various operating systems. After plugging the device in, most common operating systems will install the drivers automatically. Assuming that the driver is available and installed then to work with the device the COM Port has to be opened using the following parameters: baud rate. 8 data bits. 1 stop bit. No parity bit. No flow control. Working with the console 2 P a g e

3 In this document a description of the console functionality will be supported by examples using Tera Term open source terminal emulator working on Windows 7 operating system. This emulator can be downloaded free of charge and works with Windows 95/98/ME/NT/2000/7 operating systems. Before starting any work the BT LE RN4020 USB Dongle has to be plugged into a USB Port on the computer, and the user has to be sure that drivers were installed correctly and the device is discovered by the operating system as a standard COM Port. When this part is done the user can launch the Tera Term application. The first window which should appear asks the user to choose a connection type. On Screenshot 1 below it is shown that the proper option will be Serial with COM Port corresponding to the plugged USB Dongle. Please note that on the Screenshot 1 there is COM Port number 18 chosen but the number can be different depending upon the computer used. Screenshot 1 After clicking OK the COM Port is opened but with a different setting than is needed. To change the COM Port setting the user must click on Setup Serial Port. The Window shown on Screenshot 2 should appear on the screen after doing this. 3 P a g e

4 Screenshot 2 Here the Baud rate settings should be changed to After clicking OK the user should next change the terminal setting to make the viewing experience easier. By clicking Setup Terminal the user can enter terminal settings and window showed on Screenshot 3 should appear. Screenshot 3 Here two settings have to be changed in the New-line area. The Receive option should be changed to AUTO and the Transmit option should be changed to CR+LF. This will configure the terminal window display messages more legibly. After this whole setup, the terminal is ready to work with the USB Dongle. The user can now navigate back to the main window. If the Enter key is now pressed, the console should respond by printing {IB Technology}. This is shown on Screenshot 4 below: 4 P a g e

5 Screenshot 4 Each press of an enter key is considered by the console as a command and parsed by the microcontroller. Here the user should note that every message printed on the terminal window between brackets { and } comes from the microcontroller. This helps to distinguish between messages sent by the Microcontroller from those sent by the RN4020 module, in case any parsing software is written by the user. If the command is not recognized or an empty command is sent then the console again prints the same message showing that it is still responsive. There are few command available for the user. Please note that the command for the USB Dongle interpreter are not case sensitive. Question mark? By executing this command the user will get general information about the USB Dongle and the list of available commands. This information is shown on Screenshot 5 and may be changed when future versions are released. 5 P a g e

6 Screenshot 5 STATUS command This command can be used to report the status of the RN4020 I/O lines to the user. When using this command the Microcontroller in the device reads the I/O lines states and prints information on the screen. The default set up on power up of the device is always the same and it is as shown below on Screenshot 6. The Hardware Wake Up and Software Wake Up lines are set to 0 (LOW) and the RN4020 module is in sleep mode. Because of that PIO[1..3] lines are set to 0 (LOW) by the module. Here it is worth mentioning that every change on PIO[1..3] lines will be reported by the device console as an information string. This will be shown later in this document. 6 P a g e

7 Screenshot 6 SET command This command is used to change the state of IO lines. This command takes 2 arguments as parameters separated by a space. The first argument is the IO line whose state will be changed. There are three IO lines available: Hardware Wake Up signal HWU ; State options: 0 / LOW or 1 / HIGH Software Wake Up signal SWU ; State options: 0 / LOW or 1 / HIGH Command / MLDP mode signal MODE ; State options: CMD or MLDP The second parameter is the value of the signal to which it should be changed. For Hardware Wake Up and Software Wake Up signals the user can use LOW or 0 parameter to change the state to low, or HIGH or 1 parameter to change the state to high. For example if the user wants to change the state of the Hardware Wake Up signal to high, then the following command has to be used: SET HWU 1. Whereas changing the Command / MLDP signal to low (which means Command Mode) the following command has to be used: SET MODE CMD, and changing this signal to high (which means MLDP mode) means using SET MODE MLDP command. Screenshot 7 shows an example of changing the state of Hardware Wake Up line to high. Please note that the terminal has printed additional information: {Hardware Wake Up changed to HIGH} This is because the microcontroller detected a change of state on an I/O line. Similar information will be printed in relation to each connection between the RN4020 module and the microcontroller, and it is asynchronous. 7 P a g e

8 Screenshot 7 DIRECT command This command will change the behaviour of the console it will enter Direct Transmission State. Executing it will turn off the console and every character which is sent to the terminal will then be passed unedited and directly to the RN4020 module. This includes all possible hexadecimal characters from 0x00 to 0xFF. This option is useful when the user wants to speak with RN4020 module directly to set it up using commands described in its datasheet. As well when there is a connection established between the USB Dongle and another device in MLDP mode, the user is not limited by the console interpreter and can send binary information. To quit this mode the user has to send a BREAK signal. In Tera Term this is accomplished by pressing Alt + B keys in combination. It is worth noting here that even in this mode the Console will print any information about IO line changes, thus it is easier to recognize any change of state of the RN4020 module. Before entering the Direct Transmission State a short message will be printed by the console shown on Screenshot 8 below. 8 P a g e

9 Screenshot 8 Configuration example The configuration example presented in this chapter is related to Microchip s MLDP Demo application for Android OS. This document won t cover the installation and use of this application all necessary information can be found on Microchip s website and the application itself can be downloaded free of charge from there. This example is intended to give the user an idea how to configure and work with RN4020 module to connect it with the android app provided my Microchip and send data using it. The first step is the configuration of the module itself. The following steps have to be performed: In the console SET HWU 1 and SET SWU 1 commands must be executed. In the console the DIRECT command has to be executed to start communication with the module. In Direct Transmission Mode the following set of commands have to be sent to the RN4020 module: o sf,2 this will reset the entire settings of the module. o r,1 a reboot of the device which is needed after previous command. o sr, this sets up the module to behave as a client. o sn,ibt this sets up the BT name of the device to IBT which will appear during scanning when using the android application. o r,1 again reboot to acquire the configuration. o a,0100 this starts the advertising of the module so it can be seen by the device running the android app. 9 P a g e

10 Full listing is shown on Screenshot 9. Screenshot 9 Now after launching the android app and starting to scan the device should appear with a name IBT. After connecting with it the following information will be printed on the console: 10 P a g e

11 Screenshot 10 Please note that Screenshot 10 shows information printed by the console between brackets { and } which is a change of state detected by the microcontroller on PIO[1] line and information from RN4020 module which means that the module has established a connection. Now the user can press Alt + B key configuration to go back to the console and execute the command SET MODE MLDP which will change the mode to allow transmission of data through the module. Again executing the command DIRECT and going back to Direct Transmission State will give the ability to pass information from the console to the Android application. Full listing is shown on Screenshot 11 below: Screenshot 11 In this example you can notice that three f letter were pressed and should appear on the Android device s Text Window. Then a message from Android was passed back to the terminal window. Electrical characteristics PARAMETER Interface Power Supply VALUE Standard USB COM Port N-1 +5V ±5% USB Powered 11 P a g e

12 Current consumption Temperature range Humidity Range Bluetooth Compatibility Maximum Data Rate in MLDP mode Dimension (L x W x H) [inch] < 30 ma -30⁰C to 85⁰C 10% to 90% non-condensing V4.1 (see RN4020 module datasheet) 20 kbps x 0.8 x 0x P a g e