Here is a screenshot of an updated example tool that will do both slow, unbuffered sends as well as the fast, buffered sends. It also allows the user to play around with the baud rate during bitbang setup. You can change the baud rate and re-run bitbang setup as many times as you like, there is no need to shut down the interface to change the baud rate.
Fig 5 – Screenshot of the expanded example software
Take note of the new baud rate input box just above the setup button. Input the baud rate as a number of kiloherts – eg, 1000 for 1MHz. This is divided down by 16 in the software tool so the data rate you get on the FT232 pins is the data rate you specify.
The other new addition is the “Buffered Toggling” at the bottom. The function is the same as the last article, but with the use of buffered writes (writing all the data at once) so your bits bang at the rate specified by the data clock. Read is not yet implemented – probably once we think of a good example – but it works very much the same as writing. Upon each rising edge of the baud clock, all 8 GPIO ports are read and the data stored for later fetching by the USB software. The buffer is only 256 bytes (samples) so it must be read periodically to keep from losing data.
We hope you enjoy playing with the new tool as well as the buffered writes. As always, feel free to post your questions to our comments below, or use the Contact Us links in order to get in touch.