I/O

I/O - digital in- and outputs

The module has 8 digital I/Os (CMOS level, non-floating). The input range is 0... 3.3 V. All 8 I/Os have a weak pull-up at 1 MΩ and are set as inputs after reset.

Remark: The logic is not designed for time-critical operations; i.e. it is not a real-time operating system.

By using one or more external (max. 8) MCP23017-E (16 I/Os per IC), the total number of I/Os can be expanded up to 136. Therefore the port-expanders are connected to pins 35-37 (see application example). Because interface is I²C bus, 2 pull-up resistors need to be added (4k7):

The maximum power of the MCP23017-E is 700 mW in total. The maximum current load for a single pin is 25 mA, which makes it possible to directly operate a low current LED. If a higher load is required, the I/O current must be amplified with suitable circuitry, e.g. through an external transistor. For more details see Electrical characteristics

The overview of the software commands for the I/Os can be found under the chapter 'I/O Port'.