All CTS modules communicate with outside world though UART. A wide range of standard speeds are available, however, will recommend to use the highest available speed available on the host side.
While either ARM or AVR versions of CTS can handle 921600 bauds without hiccups, this speed may not be available if CTS will be connected to other MCU boards due internal clock limitations (e.g.: Arduino running @16 Mhz have 3.7% errors @115200 bauds and almost 8% @230400 bauds).
For convenience and for future software upgrades, beside UART connector, all boards come equipped with standard ISP (CTS AVR) or JTAG (CTS ARM) connectors.
To keep the cost down and also the size, there is no dedicated power connector on the board. To power it up, the UART connector will be used instead.
CTS AVR 5.1, top PCB silkscreen.
CTS boards are designed to follow the FTDI connector, as such, a 5 pin, 0.1″ pitch header can be attached. By default, there is no connector or pin header mounted, instead, user can decide what kind of connection will be more suitable based on application and available space.
The pin definition is marked on the silkscreen of each board (see above picture).
UART header pinout on CTS board.
A standard 6 pins AVR ISP header is available on all CTS AVR boards (on both CTS AVR 5.1 and CTS AVR 5.2).
AVR ISP header on CTS board.
AVR ISP pinout.
ARM SWD JTAG
Due size limitations a standard 10 pin SWD JTAG 0.05″ connector is used for JTAG programming on the CTS ARM boards.
ARM SWD JTAG (0.05″ 2 x 5 ways) header on CTS board.
SWD JTAG (0.05″ 2 x 5 ways).
A 16 pin (2 x 8 pins) camera connector is available only on CTS AVR 5.1 boards and use the same pinout as all OV7670 and OV7725 camera modules available cheap online:
CAMERA header on CTS AVR 5.1
OV7670/OV7725 Camera connector pinout.