OK guys...I have done some checking on reciever voltage requirements and here is what I have found.
First of all, you can measure the voltage being supplied by your serial port by measuring the voltage across pin 4 and 7. If you are looking straight at the end of your serial DB9 Plug, Pin 4 is the pin on the bottom row far left and Pin 7 is the top row, middle pin.
The receiver circuit has a transistor for reverse voltage protection and also a voltage regulator to drop voltage input down to 5V. If the voltage being supplied by your serial port is Less Than about 7.5V then you are not getting enough power to your receiver.
I am working on a workaround to bypass the voltage regulator, I have it working here and it enables my KeySpan USB-Serial adapter to power the device. My KeySpan USB-Serial only provides 5.79V across pins 4 & 7 and when I put the workaround in place, it drops to 4.3 supplied to the receiver. I am waiting on word back from the supplier to see if 4.3V is enough as the specs say it needs 4.5V.
If you are having droppouts and want to check the voltage that your PIC and receiver are getting, you can check the voltage across Pin 1 & 8 on the PIC chip which are the two pins at the top by the notch.
Stay tuned for more as I figure it out.
PiperPilot
First of all, you can measure the voltage being supplied by your serial port by measuring the voltage across pin 4 and 7. If you are looking straight at the end of your serial DB9 Plug, Pin 4 is the pin on the bottom row far left and Pin 7 is the top row, middle pin.
The receiver circuit has a transistor for reverse voltage protection and also a voltage regulator to drop voltage input down to 5V. If the voltage being supplied by your serial port is Less Than about 7.5V then you are not getting enough power to your receiver.
I am working on a workaround to bypass the voltage regulator, I have it working here and it enables my KeySpan USB-Serial adapter to power the device. My KeySpan USB-Serial only provides 5.79V across pins 4 & 7 and when I put the workaround in place, it drops to 4.3 supplied to the receiver. I am waiting on word back from the supplier to see if 4.3V is enough as the specs say it needs 4.5V.
If you are having droppouts and want to check the voltage that your PIC and receiver are getting, you can check the voltage across Pin 1 & 8 on the PIC chip which are the two pins at the top by the notch.
Stay tuned for more as I figure it out.
PiperPilot
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