I've been studying about USARTs and I haven't seen a consensus on synchronous USART implementation among MCU producers.
First of all, there are transmit and receiver clock lines on some serial connectors (e.g. 25-pin RS-232 connector). However, I couldn't find any USART device (within a MCU) which provides both of these lines.
Secondly, as far as I learn, synchronous mode doesn't define start and stop bits but some synchronous USART devices use these bits.
Thirdly, some synchronous USART devices, such as in PIC16F882 (page 171), use a bidirectional data line to transmit and receive data. Hence, only half-duplex synchronous transmission is possible with these devices.
I want hands on experience on a complete synchronous USART device using a common serial connector like 25-pin RS-232. Here are some ideas come to my mind.
Bit banging may be an appropriate way to study about protocol (but not device itself).
Custom hardware design would be a good experience but it's pretty harder than dealing with ready devices.
Combining two PIC16F882s, one for receive only and one for transmit only may be a solution.
My problem is I cannot find a complete(!) device to study USART, write some code, inspect registers etc. I need suggestions and I'm open to new suggestions and references.