Instructions | FTDI cable header replacing MAX232 circuit

1

Omit or remove the MAX232 chip and capacitors

NB: This project only works for DIP chips, not the surface-mount chips.
2

Fit a 6-pin header in pins 1 to 6 of the MAX232 chip site

These pins were for the charge-pump capacitors, which have been omitted or removed.
Pin numbers are the same for the header and the IC socket holes.
3

Wire pin 1 of the FTDI cable header to pin 15 of the MAX232 site (Ground)
4

Wire pin 3 of the FTDI cable header to pin 16 of the MAX232 site (VCC) if your project can be USB powered

NB: The most you can rely on a USB providing is 100 mA at 5 volts.
You MUST select a cable that provides the logic levels AND the VCC your project uses, i.e. 5, 3.3 or 1.8 volts.
DO NOT treat these cables as hot-pluggable or interchangeable with other cables.
In fact, it is safest to fasten the cable to the project so that it cannot be easily changed.
5

Wire pins 4 (TXD) and 6 (/RTS) of the FTDI cable header to pins 12 and 9 of the MAX232 site (serial inputs)

Check which MAX232 pin your project uses for TXD and /RTS.
If it does not use the latter, the TTL level /RTS will be tied low by the project circuit.
6

Wire pins 5 (RXD) and 2 (/CTS) of the FTDI cable header to pins 11 and 10 of the MAX232 site (serial outputs)

Check which MAX232 pin your project uses for RXD and /CTS.
If it does not use the latter, tie /CTS low to tell the USB cable it is clear to send data to the project at any time.
7

Check your wiring

And no
8

Plug your cable in your unpowered project, the right way round.

And you are ready to try it out.

FTDI cable header replacing MAX232 circuit

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