Remzibi’s OSD Serial Communications
Serial Communications Overview
Opening the Serial Communications screen
The serial cable communications screen can be accessed three ways.
1) Click Tools, Serial Communication from the main screen
2) Click “F6″ from the main screen
3) Press the “Serial Communications” button on the main screen
The serial communications screen has several functions. It can test the USB to serial port to verify that communications are working. It can upload your layout (BIN) information and fonts to the OSD. It can download from the OSD. Finally, it can calibrate the ADC’s, which will be explained further into this manual.
The first step to using your OSD is to run a test to make sure the cable is able to communicate with the OSD correctly. When you run the software for the first time, it will prompt you to run this test. It is not necessary to run the test routine every time you program your OSD, only the first time or any time you are having problems communicating with the OSD.
Normal/Programming Modes
Your OSD has two modes. “Normal” mode and “Programming” mode. If you connect power to the OSD without holding down the red button, you will boot in Normal mode. This is how you connect using the GPS or GPS emulator or to update the firmware. If you connect the power with the reset button pressed, you will enter Programming mode which is used for uploading, downloading and ADC calibration.
Connecting OSD in programming mode
USB TTL Driver DownLoad: PL2303_Prolific_DriverInstaller_v1210
Remzibi’s OSD Configuration Tool PC Software: http://www.happykillmore.com/Software/RemzibiOSD/Setup/Setup.exe
Step 1) Connect your USB cable to your computer.
Step 2) Connect your USB cable to the OSD.
Step 3) Connect a battery to the +Power- connection while holding down the reset button on the OSD.
Step 4) Release the reset button on the OSD.
Step 5) Open the Serial Communications screen on the PC software.
Step 6) Click the magnifying glass button (to find the COM port with the cable connected) and click Connect (or select the COM port manually and click conect).
Step 7) From the “Serial Cable Setup” tab, click “Start Test.”
If everything worked as expected, you should see “Status: Passed (Firmware v#.##)” If not, you’ll need to figure out if the operating system has a problem with the cable or if the wrong COM port has been selected.
Troubleshooting your USB to serial driver
To troubleshoot a bad connection, you’ll need to open the “Device Manager” and expand the “Ports (COM & LPT)” branch and find the “Prolific USB-to-Serial Comm Port (COM##)” and make sure the OSD sofware is using the right COM port. If it’s missing from the device manager screen, you may need to reinstall the drivers which can be found in the C:\program files\Remzibi OSD\USB Programmer\1.12.35 folder on your computer. Try running Setup6858.1.12.35.exe again and disconnect and reconnect your USB to serial cable. That should add the driver to the Device Manager screen. If that doesn’t work, you might want to try a different USB port or you may have something wrong with your USB cable or operating system.
Show/Hide Communcations Log
By clicking Show or Hide at the bottom left you can open or close the communications log. Generally, you will not need to see the specific commands being sent or received by the OSD. However, in specific cases, you can use this function to send commands directly to the OSD. If you click the Show button and enter “VER” (no quotes) and hit Send, the OSD should respond with the verision number in the box on the right.
Upload Program & Font
Uploading Program (BIN Files) & Fonts
Step 1) Connect the OSD in programming mode (reset button down while connecting power).
Step 2) Check one or more of the following options
# Upload BIN (Program) Data – This will send your layout information to the OSD
# Upload ADC Data (Gain & Min) – By selecting this you will overwrite your existing gain and min information from your previous calibrations. Generally, you do not want to select this option.
# Upload Selected Font – If you have made a change to the font file or have a new font file on your computer you’d like to use, select this option.
Step 3) Click Upload to OSD.
Uploading the BIN (Program) Data will take about 30 seconds. Uploading the Font file will take about 4 1/2 minutes. Remember, you only need to upload the font files if you’ve made a change or want to upload a different font.
Downloading Program (BIN Files)
Step 1) Connect the OSD in programming mode (reset button down while connecting power).
Step 2) Click “Download from OSD”
This process will grab the BIN file data from the OSD and overwrite what’s in memory on the PC. When you click Exit on the Serial Communications Screen, the layout will refresh and show you how things are configured on the OSD. Please be careful. If you’ve opened a file and have made changes, downloading from the OSD will overwrite what’s in memory and if you hit save, it will overwrite the file.
ADC Configuration (Basic)
ADC stands for “Analog to Digital Converter” and is a built-in process on Microcontrollers (like the Atmel chip on this OSD). It’s purpose is to convert an analog voltage into a digital number so that a math function can be completed on it. The value of the digital number is not really important, but it is important to tell the microcontroller what that value means so it can display the correct value on the output. So an input of 12.0V on the analog input of the ADC may convert into 746 as a digital readout. That value is then scaled using a “Gain” value and adjusted using a “Min” value.
On the Basic ADC Setup, you don’t have to worry about what the gain values or min values are, you only have to worry about the input voltage.
Each ADC has an alarm value which will cause the header symbol in front of the ADC’s value to flash. By default the Voltage-Motor (ADC0) and Voltage-Video (ADC1) are set to the “Less Than” alarm type meaning when the voltage drops below the alarm value, the symbol will flash.
Using the Basic ADC Setup
Step 1) Connect the OSD in programming mode (reset button down while connecting power).
Step 2) Using a Multi-meter (preferrably NOT a Watt-meter), measure the voltage on two battery packs.
Step 3) Connect the battery packs to the OSD.
Step 4) Open the Serial Communications screen and select Basic ADC Setup.
Step 5) Click “Start Polling” (This will start asking the OSD for the current ADC values for both Vvid and Veng batteries).
Step 6) Highlight “Voltage-Motor” and type the battery’s votage (ie 12.0) in the current voltage field and an alarm value (ie 9.0) in the alarm value field.
Step 7) Highlight “Voltage-Video” and type the battery’s votage (ie 12.0) in the current voltage field and an alarm value (ie 9.0) in the alarm value field.
Step 8) Click “Program OSD”
ADC Configuration (Advanced)
For those users who wish to attach other devices to the OSD, the Advanced ADC is for you. Temperature sensors, current sensors, RSSI (RX signal strength) or any other sensor (with the exception of Frequency Counter – which has it’s own dedicated object on the OSD) can be connected as long as it puts out an analog voltage based on it’s measurement. You’ll need to include a resistor and possibly a capacitor between the sensor and the OSD board to protect the OSD’s microcontroller. For more information, please read the Poor Man’s OSD thread on RCGroups.com.
You are going to need be able to make the sensor function while using the Advanced ADC setup in the OSD’s software. The two critical items are the “min” value which means “what is the zero value” and be able to make the sensor function as close to the max as possible to adjust the “gain” value.
Using the Advanced ADC Setup
Step 1) Connect the OSD in programming mode (reset button down while connecting power).
Step 2) Open the Serial Communications screen and select Advanced ADC Setup.
Step 3) Click “Start Polling”
Step 4) Put the sensor in it’s zero state. Read the “Current ADC” value and try this into the “Min Value” field.
Step 5) Put the sensor in it’s max state.
Step 6) Click the “Desired Output” field and enter what you’d like to be shown when the sensor is at it’s max (ie 100).
Step 7) Enter an alarm value.
Step 8) Click “Program OSD”
Positive Gain
Above, we assumed that the max ADC value is greater than the min ADC value. This means we have a positive gain. If the max ADC is less than the min but you’d like to view it as 0-100 where 100 is the max, see the Negative Gain section below.
In the steps listed above, the Gain value was automatcially calculated when the “Desired Output” field was modified. It doesn’t have to be done this way. Here is another way: Let’s say a temperature sensor puts out a digital value of 129 when it’s at 0癈 and a digital value of 563 at 100癈. We could enter 129 for the “Min Value.” To calculate the Gain, we take Output / (ADC – Min) = Gain = 100 / (563 – 129) = 0.23041.
So as an example, if the ADC reads 412 then the output = (ADC – Min) X Gain = (412 – 129) X 0.23041 = 65.2癈.
Negative Gain
Let’s say you’re trying to use the RSSI (Received signal strength indication) output from your RX and the peak/max ADC value is 322 and the min ADC value is 840. But you’d like to show 0 when there is no signal and 100 when there is peak signal. You need to use a negative gain in this situation.
In this situation, you’ll need to enter the min ADC value (ie 840) in the “Min Value” field.
Then you’ll need to calculate the gain. Gain = Output / (ADC – Min) = 100 / (322 – 840) = -0.19305.
So in the example above:
If the ADC reads 711, Output = (ADC – Min) X Gain = (711 – 840) X -0.19305 = 24.9% (This would be a low signal strength)
If the ADC reads 405, Output = (ADC – Min) X Gain = (405 – 840) X -0.19305 = 84.0% (This would be a high signal strength)
Frequency Counter
The frequency counter does not use the Serial Communications window. It is configured directly from the main screen by highlighting the “Frequency Counter” object and entering a gain value in the gain field. Typically, this will be 1 / {Number of detectors}. So if you’ve got a detector on each of your 3 blades on a propellor, your gain will be 1 / 3 = 0.33333 so for every revolution, the sensor will trigger 3 times X gain of 0.33333 = Actual RPM.