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Serial Ports

The MCBSTR9 board connects the two on-chip serial UARTs to the ST3232 (IC7), which converts the logic signals to RS-232 voltage levels.

MCBSTR9 Board Serial Ports

The serial ports (COM1 and COM2) are configured as a standard 3-wire interface. The DB9 connector is wired to loop the PC's handshaking signals back to the PC. Refer to the figure below for details.

Serial Ports Loop Back DB9 Diagram

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