GY-63_MS5611/libraries/PinInGroup

PinInGroup

Arduino library to group reading to 16 input pins in one command

Description

A PinInGroup holds a number of input pins that can be read by means of a single read() command. The PinInGroup makes it easier to work with a number of inputs that act as a logical unit. Think of reading a parallel bus or read 4 lines from a matrix keyboard, or an array of switches.

One of the interesting possibilities of the pinInGroup is to add a single pin multiple times. That allows one to read a pin e.g. in a burst of 8.

Another application of adding a pin twice could be reading a pin as first and as last of a group. This allows you to check that state of e.g. a parallel bus has not changed during read.

Performance

The PinInGroup is not more efficient as reading the pins in a loop yourself. Hoewever it is less programming and can give clearer code.

Note that the pins are not read at the same microsecond. A small time is needed to go through all pins. This is platform, group size and pin state dependent.

Interface

Constructor

• PinInGroup() Constructor

Administration

• clear() sets the size to zero so one can repopulate.
• add(size, pinArray, mode) adds a predefined array of pins to the group. Returns the number of pins added.
• add(pin, mode) adds a single pin to the group. Returns the number of pins added (1 or 0). Mode can be INPUT(default) or INPUT_PULLUP.
• getPin(idx) idx = 0..15; returns the pin at slot idx or 255 (0xFF) when out of range
• getIdx(pin) returns the (first) index of the slot with pin number. 255 (0xFF) if not found.
• isInGroup(pin) returns how often a pin is added to a group. Can be more than once.
• size() how many slots are used
• available() how many slots are free

Read

• read() reads a 16 bits unsigned int from max 16 pins. Every bit represents an input value. Note that the bits are in LSB order of the adding.
• read(idx) idx = 0..size-1. Reads the single pin at idx from the group. Returns 0 or 1 if OK and 0xFFFF when idx >= size.

Future

• Optimize the low level reading e.g. reading registers only once.
• Hold register and bit info per pin. Especially for AVR this could be interesting.
• Create an analogPinGroup and a PWMGroup
• extend to 32 bits / pins.
• Allocate dynamic memory? (fragmentation)

These ideas will be explored when time permits.

Operation

See examples