INPUTTYPE mask

Mask - is a variable/constant which specifies the input pin type.

Make pin an input of hardware silicon type TTL (0) or ST (1).

Microcontroller inputs can be of two types, TTL compatible or ST (Schmitt Trigger). On most PICAXE chips this type is predefined by the internal silicon design and cannot be changed and most chips have a mixture of both types. See the tables below for more details about the type of each PICAXE chip input.

Wiith improvements in silicon technology, on the more recent M2 parts, each input can be user configured to be either the TTL (0) or ST (1) type.

The type is defined by a mask which is a word length value where bits 0-7 correspond to B.0 to B.7 and bits 8-15 correspond to C.0 to C.7. Setting a bit to 1 makes it a ST type input, setting a bit to 0 makes it a TTL type (power up value is 0, TTL, on all pins).

The differences between TTL and ST input pin types are as follows:

Values between the high and low voltages are 'floating' and cannot be reliably used as either a high or low signal. Therefore in general TTL inputs are considered more versatile, as, for instance, at a 5V supply they will be guaranteed a 'high' signal at above 2V instead of at above 4V. However on some occasions Schmitt Trigger inputs may be desired.

Input Pin Types:

* 14M2 pins can be reconfigured via 'inputtype' command

* 20M2 pins can be reconfigured via 'inputtype' command