Hi all, I created a thread before and I think I have gone ahead of myself.

Is it possible to send a serial data byte and 8 individual bits at the same time?

The idea is to send serial data on the rs232 txd pin while sending 8 bits on the dtr pin.

If not I may have to have a microcontroller involved.

 

If not using a Micro now, what are you using?
I don't see how you can simultaneously send 2 x 8bits on a single UART!
What is the need for it over two consecutive bytes?
Max.

 

I used to have a book ( Still got it somewhere) that had software that allowed serial port, joy port and parallel port bit access.. You could achieve two serial comms side by side using bit banging..

There were 4 pins each way on the 9 pin serial port... BUT!! You couldn't use the serial module at the same time.. Although! Reading through your posts you are using USB so you don't have the same access anyway!...

 

The idea was to use the TXD, DTR and CTS RS232 output pins directly to a shift register.

TXD would be the shift register clock
DTR would be the serial data pin
CTS would be the storage register clock

 

Okay... You are using 74HC595 serial load latch registers.... Normally the CTS is an input on the PC so You would use the RTS as the storage clock BUT!! you have no control over the TXD pin so the TXD pin would have to be the storage... If you bit bang the RTS and DTR then send 0xff to the serial port the signal would be a clock pulse...