USB - TTL UART

FT232RL board, USB left, TTL right

My descriptor embedded in the FT232RL

Serial comms setup

I had been looking for a usb interface solution for a piece of home-made gear when an old friend, who is a professional electronics engineer, reminded me of FTDI's range of interface chips. He even gave me one to play with; the 28 pin FT232RL. It's a USB-TTL UART device. So I did some experiments to practise using it.
First I made a circuit to use it as a usb powered device. After installing the drivers on a pc, I could see another usb(com) port had been detected. Then with a few more components added to the circuit I used it in my intended application as a self-powered usb device.
I programmed the user area of the chip's eeprom with my application data and some configuration options, e.g., allocating a couple of pins as outputs for LEDs. I was pleased to see that the same data I had just programmed in now appeared in the usb connection properties window.
Confirmation that the circuit was functioning correctly came when the red and green LEDs flashed in response to sent and received data between the PIC EUSART on MYDEV2 development board and the host pc running serial communications software.

More details of my low power transmitting setup for longwave

Since the posts on 22nd February and 8th May, I have received requests to post more information on the setup I used for my low power test transmissions on the longwave 2190m band.

The circuit schematic and pcb artwork for the AF amplifier are shown above; click on the images to expand them. The original size of the artwork is 70 x 100mm. The pcb is single-sided; top component layer, bottom copper layer. Anyone wishing to copy my pcb design might need to modify the tracks connecting T1, depending on the actual transformer which is available and the windings used.

A +18V dc power supply can be used for greater output power. I didn't try this only because I don't have a convenient way of providing that voltage, and also the fan is a 12V unit.