Using MINI-MAX boards with Hyper Terminal

The null modem cross cable that comes with MINI-MAX and PRO-MAX boards crosses RTS and CTS lines from one end of the cable to the other end. Since Hyperterminal and many other terminal programs control the RTS line, these programs keep the MINI-MAX and PRO-MAX boards in Program Mode.

There are few easy solutions to this problem:

1) Use a simple RS232 cable that connects only Transmit, Receive and Ground lines. Since RTS is not connected, Hyper Terminal will not be able to put the board in Program Mode. Here is the wiring diagram of a simple RS232 cable:

Serial Cable

2) Cut the RTS and CTS lines of CNM1-9F9F-6 Null Modem Cross Cable that came with the board. The pinout would be as follows:

Null modem cable

To use the same cable for both downloading and for Hyper Terminal, you can put a switch on RTS line so you can toggle back and forth between Download and Hyper Terminal modes:

Null modem cable

NOTE: When the serial cable is disconnected from the board, the board automatically goes to RUN Mode. This means the PC does not need to be connected to the board to execute a program.