PIC Tutorial - RS232 Board


RS232 Board

This is the RS232 board, it uses a MAX232 5V to RS232 converter chip, this converts the 0-5V TTL levels at the PIC pins to the +12V/-12V levels used in RS232 links. As is common with these devices it inverts the data during the conversion,  the PIC USART hardware is designed to take account of this - but for software serial communications you need to make sure that you invert both the incoming and outgoing data bits.

The top two jumpers (Jmp1 and Jmp2) on the RB7 and RB6 lines are for connection to the 16F876 board (the 16F876 uses RC6 and RC7 for it's USART connection), and the tracks should be cut feeding RB1 and RB2, as in the third graphic below. The bottom two jumpers (Jmp3 and Jmp4) on the RB1 and RB2 lines are for the 16F628 board (the 16F628 uses RB1 and RB2 for it's USART connection), and the tracks should be cut feeding RB6 and RB7, as in the second graphic below.

So, for use with the 16F876 board cut the two tracks shown to RB1 and RB2, for the 16F628 cut the two tracks RB6 and RB7. This only applies if you are using the hardware USART, for software serial communications you can use any pins you like.

Although it's labelled as connecting to PortC for the 16F876 processor board (and is also designed to connect to PortB for the 16F628 processor board), as with most of the boards, it can also be connected to other ports if required, and if not using the hardware USART.

This is the top view of the RS232 Board, there are four wire links, the three veropins at the bottom right are the connections to the 9 pin D socket. The board can be configured to use pins B1 and B2 for a 16F628 series, or C6 and C7 for a 16F876 series.
The bottom of the RS232 Board, it has sixteen track breaks, this example is configured for B1 and B2, for a 16F628.
The bottom of the RS232 Board, it has sixteen track breaks, this example is configured for C6 and C7, for a 16F876.

Double RS232 Board

This is an updated RS232 board, it uses both halves of the MAX232 to give two serial ports, one in hardware, and one in software, it's essentially the same as the previous board, just expanded slightly.

This is the top view of the double RS232 Board, there are six wire links , the three veropins at the bottom right are the connections to the 16F876 UART 9 pin D socket, the three veropins at the middle right are the connections to the 16F628 UART 9 pin D socket.
The bottom of the Double RS232 Board, it has fourteen track breaks.

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