University:
Boston University
Course:
CAS CS 111 | Introduction to Computer Science 1
Academic year:

2023
Views:

260

Pages:

14
Author:

Enzo Knapp

USB TTL Module v1 Guide 1. Introduction The Black Box ToolKit USB TTL Module enables you to quickly and easily TTL event mark from any Experiment Generator or other software that supports a standard serial port under Microsoft Windows. It can be used in any environments where there is a need to event mark, e.g. EEG, eye tracking etc. You should bear in mind that the TTL Module is locked to the time domain of your Experiment Generator, i.e. when you instruct it to produce a TTL signal you are relying on your Experiment Generator to output the serial bytes required at the time you request them. For an example of what this may mean for your experiment you are advised to consult section 5 of this guide. The Module itself is designed to act as a parallel port replacement for PCs that have only USB ports and has 8 TTL input lines and 8 TTL output lines. You have the option of using existing parallel cables to interface with your own equipment via the male 25-way D connector. Alternatively you can make use of the optional BBTK USB TTL Module breakout board (shown below) which is connected to the Module by the supplied 25-way parallel cable. Using the Module to event mark is simple. Once installed all you need do is open the linked serial port and send a two byte hexadecimal string. For example to event mark on TTL Output Line 1, open the serial port and send the hex bytes 01. To stop send 00. To receive incoming TTL signals sent from your equipment on the TTL Input Lines you would monitor the serial port for two bytes being received, e.g. 01 indicates that your equipment has sent TTL Input Line 1 high (+5V). Examples of event marking a stimulus onset and duration are shown below for several popular packages. Note that these are simple examples and that you are responsible for proper implementation. Before each use you should ensure that the serial port driver is installed and configured correctly (see section 2) and that timing validation checks have been carried out (see section 3). PsychoPy E-Prime® MATLAB import serial ser = serial.Serial(0, 115200, timeout=1) ser.write('01') ser.write('00') ser.close() Serial.WriteString “01” Serial.WriteString “00” s = serial('COM1'); set(s, 'BaudRate', 115200, 'DataBits', 8, 'StopBits', 1, 'Parity', 'none'); fprintf(s, '01'); fprintf(s, '00'); fclose(s); 1.1 USB TTL Module Pinouts If you have chosen not to purchase the optional breakout board you may need to make up your own parallel cable which maps to your specific devices TTL Input and Output pins based on the Modules front facing 25-way D pinouts below. Pins 2~9 correspond to TTL Output Lines 1~8 and pins 10~17 to TTL Input Lines 1~8. Pins 18~25 are grounds. The rear of the module has a standard USB type B connector by which it is connected to the PC doing the event marking. Green and Red activity LEDs show Input and Output activity respectively. 2. Using the USB TTL Module for the First Time 2.1 Installing the Serial Port Driver Before you can use the USB TTL Module you must install a simple driver and configure it correctly. This ensures that the Module appears to your system as a standard serial or COM port. The exact process will vary depending on your Operating System. The example below covers Windows 7 and assumes that Windows Update will automatically supply the required drivers. For Windows 8, 8.1 and 10 the process is virtually identical. For Windows XP and Vista you will find a Drivers folder on the installation CD. A Drivers folder is also installed with the Modules configuration utility. Before installation ensure that you are logged in with local administrator rights. Using the supplied USB cable plug the USB TTL Module into a primary USB port. That is, a USB port that is not shared with another device or is part of a hub or switch. This should be a full speed USB 2 or 3 port. The Green and Red LEDs on the rear of the Module will illuminate for 10 seconds as it initialises each time it is plugged in. The very first time you plug in the Module it will be identified and drivers should be automatically downloaded for it from Windows Update as shown. As the drivers are downloaded a tick will appear next to each component. As part of the final step the Module will be assigned a USB Serial Port COM number. In this example, COM4. This is the serial port you would connect to the USB TTL Module through in order to event mark. 2.2 Troubleshooting Installation of the Serial Port Driver Depending on how your PC is setup you may need to manually tell Windows to use Windows Update to install drivers for the USB TTL Module. Do this by clicking on the Change setting… button. Next click on Yes, do this automatically (recommended). The required drivers will then be automatically downloaded as shown in section 2.1. You also have the option to click on No, let me choose what to do, and select a one off driver installation from Windows Update. If you are not connected to the Internet you can install the drivers from the installation CD. A Drivers folder is also installed with the Modules configuration utility. Your Operating System may automatically prompt you to select the folder where the drivers are located in which case you should select the Drivers folder. Alternatively you can run a standalone driver package from the Drivers folder if your Operating System does not automatically prompt you. Run the 64 bit version for 64 bit Operating Systems. Run the 32 bit version for 32 bit Operating Systems. 2.3 Configuring the Serial Port Driver Before you make use of the USB TTL Module for the first time you need to set the latency at which it operates. By default it sends and receives in 16mS busts which is too slow for event marking and needs to be manually set to 1mS. If you have not configured the Serial Port Driver correctly the Black Box ToolKit Ltd cannot be held responsible for inaccurate event marking. Once configured you should install and run our Configuration Utility which validates how quickly you can event mark using your particular PC and the USB TTL Module. To configure the Serial Port Driver, press the Windows Key+R, and type “devmgmt.msc”. Then click on OK. This will open the Windows Device Manager. Right click on the USB Serial Port where the BBTK USB TTL Module was installed. Then click on Properties. Click on the Port Settings tab and then on Advanced… Under Advanced Setting for COMx you should select a Latency Timer (msec) of 1mS using the drop down box. To apply the new settings click OK. To close the Properties dialog click on OK again. 3. The BBTK USB TTL Module Configuration Utility 3.1 Installing the Configuration Utility Before you carry out any event marking you should validate the timing latency on your particular PC. To do this you will need to make use of the BBTK USB TTL Configuration Utility. This utility can determine if the Serial Port Drivers have been installed and configured correctly as shown in section 2. Crucially it carries out internal tests which determine the timing latency of your PC and Operating System when using the USB TTL Module. Ensure you are logged into the local PC with Administrator rights and insert the CD into your CD drive. The setup should automatically run. If not you may need to manually run setup.exe. If the Microsoft .NET 4 Framework is not installed on your PC you may be prompted to download and install it. An offline version is included on the CD under the DotNetFX40 folder. If you wish to use this press Cancel, install the Framework and the rerun the BBTK USB TTL Module setup and continue as below. Before you can install you will need to Agree to the License Agreement. Select the folder where you want to install the BBTK USB TLL Module. In general you should select Everyone who uses this PC so that everyone who has an account on the PC can use the Configuration Utility. Next confirm installation. At this stage you may be prompted by UAC to confirm the application Publisher. Click on Yes to continue. The BBTK USB TTL Module Configuration Utility will now be installed. To finalise the installation click on close. To start the BBTK USB TTL Module Configuration Utility click on its icon from the Start Menu. 3.2 Validating Event Marking Latency Before using the USB TTL Module for event marking you should use the Configuration Utility to carry out USB TTL Latency Validation Checks. These checks help determine how quickly the Module can event mark from your particular PC over USB. If you have not configured the Serial Port Driver correctly or if you have not run USB TTL Latency Validation Checks The Black Box ToolKit Ltd cannot be held responsible for inaccurate event marking. The OUTPUT Auto Test determines the potential latency of your event marks for the PC you are hosting the USB TTL Module on. This sends a series of event mark pairs to the Module with the Modules hardware timing recording the latency between each one in microseconds (uS). This hardware based elapsed time is returned to the Configuration Utility after each pair. In total 50 event marks are sent to the Module in sequence as rapidly as possible. To begin start the Configuration Utility. When first run the COM port will be set to COM99 and you will need to choose the correct serial COM port on your system. To choose the COM port click OK. Under Current driver settings the COM port with the USB TTL Module attached should be automatically selected (red arrow). Note that the Latency Timer (mS) should be set to 1mS as detailed in section 2.3. If it set to any other number you should carry out the procedure to set it to 1mS. If the correct COM port is not selected pick it from the drop down box and then click Apply. If you have chosen the correct COM port and the USB TTL Module is attached then the Status LED will change from red to green as shown and the interface will be unlocked. To carry out the latency check click on Auto Test. The test will be flagged as being passed if the mean latency is consistently under 1mS. If the test is not passed on your PC you are advised not to use the USB TTL Module for live event marking as timing consistency cannot be reliably attained. In this case the mean latency to event mark is: M = 0.25mS, SD = 0.02mS If the mean event marking time is longer than 1mS you will be warned and advised to check the COM Port Driver latency and offered help on how to do this. An example of a test failure is shown below. In this example the test has been failed as the Latency Timer (mS) has been left set at the default driver installation value of 16mS. The Latency Timer drop down label has also turned red to indicate a value greater than 1mS. If the COM Port Driver is set to a value greater than 1mS a warning dialog will be displayed. If you have not configured the Serial Port Driver correctly or if you have not run USB TTL Latency Validation Checks The Black Box ToolKit Ltd cannot be held responsible for inaccurate event marking. Should the Serial Port Driver latency be set to 1mS and your PC still doesn’t pass the latency Auto Test you are advised not to use the Module for time critical event marking. 3.3 Checking Input Latency The Configuration Utility also allows you to check input duration timing. This test measures the time between TTL signals on TTL Input Line 1 going high to low, e.g. a EG pulse from a Black Box ToolKit v2, button press, on|off, +5V to 0V. You should note that this Configuration Utility uses Windows based timing for this test in addition to displaying timing measures live therefore its accuracy is subject to some variability as a result. To start the input duration test click on Start. As each input is received its duration is displayed. To stop testing input durations click on Stop. 3.4 Checking TTL Inputs Coming From Connected Equipment Often it’s useful to check that your equipment is connected to the USB TTL Module correctly and is outputting TTL signals correctly, e.g. start sequence signals. Remember TTL Inputs on the Module are +5V TTL outputs FROM your equipment. For you to be able to check TTL Inputs the green status LED should be lit bright green and the 8 green TTL Input LEDs should not be greyed out. The Configuration Utility is simply designed to show if the TTL Input Lines are connected correctly. The green Input LEDs may not be a real-time representation. By default the 8 green TTL Input Line LEDs are off as long 0V is being input. Lines are displayed in binary order from right to left, i.e. 128, 64, 32, 16, 8, 4, 2, 1 Each line corresponds to the D pin numbers shown, e.g. Input Line 1 corresponds to D pin number 10 and so on. The hexadecimal value of the Input port is also shown in the Hex box. This shows the value of the two bytes been sent from the Module itself. It is these two bytes you should monitor in your own software when detecting TTL Inputs being fed into the Module. In this example Input Line 1 has gone high with a hex Input Port value of 1 and the appropriate green LED has illuminated (D pin 10). In addition the green input LED on the Module itself will also illuminate. Hex two byte values can range from 00~FF (hex), 0~255 (dec), 00000000~11111111 (bin) to represent the status of each Input Line on the Input Port. 3.5 Checking TTL Outputs Going To Connected Equipment Often it’s useful to check that your equipment is connected to the USB TTL Module correctly and is receiving TTL signals correctly, e.g. event marks. Remember TTL Outputs on the Module are +5V TTL outputs TO your equipment. For you to be able to check TTL Outputs the green status LED should be lit bright green and the 8 red TTL Output LEDs should not be greyed out. The Configuration Utility is simply designed to show if the TTL Output Lines are connected correctly. The red Output LEDs may not be a real-time representation. By default the 8 red TTL Output Line LEDs are off as long 0V is being output. Lines are displayed in binary order from right to left, i.e. 128, 64, 32, 16, 8, 4, 2, 1 Each line corresponds to the D pin numbers shown, e.g. Output Line 1 corresponds to D pin number 2 and so on. The hexadecimal value of the Output port is also shown in the Hex box. This shows the value of the two bytes being sent to the Module. It is this two byte value you should send to the Module from your own software when you want to event mark on those lines. To send a given TTL Output Line high (+5V) click on it. To send it low (0V) click on it again so that the LED is not illuminated. In this example Output Line 1 has been sent high with a hex Output Port value of 01 and the appropriate red LED has illuminated (D pin 2). In addition the red output LED on the Module itself will also illuminate. Two byte hex Output values can range from 00~FF (hex), 0~255 (dec), 00000000~11111111 (bin) to represent the status of each Output Line on the Output Port. To clear all lines at once (0V) click on the New toolbar button or press CTRL+N.

USB TTL Module v1 Guide Chapter 1

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