NAME

hal_mcp23017 - Userspace HAL component to connect a MCP23017 port expander

SYNOPSIS

loadusr -W hal_mcp23017 [options]

DESCRIPTION

hal_mcp23017 is a userspace HAL component which connects to a Microchip MCP23017 port expander by i2c bus. It can set output pins and read input pins and can configure all aspects of the chip like interrupt creation by the interrupt on change feature of the chip.

The inputs and output of the chip are configured by the -iodira and -iodirb options and are reflected by corresponding HAL pins in the component. A output pin of the chip is created as input pin in the component with a name ending to .out and a input pin of the chip is created as output pin in the component with a name ending to .in

The IO expander is not suitable for high speed port bit changes. However, it can be used for controlling devices like coolant or tool changer.

OPTIONS

• -verbose
  Turn on verbose messages. This prints major code flow steps.

• -debug
  This also turn on verbose messages Turn on debugging messages. Debug mode prints I2C actions.

• -name (default hal_mcp23017)
  Set the name of the HAL module. The HAL comp name will be set to , and all pin and parameter names will begin with .

• -i2cbus
  Bus number of the I2C bus the MCP23017 port expander is attached. Default: 2

• -address
  I2C address of the MCP23017 port expander in the i2c bus. Default: 0x20

• -iodira
  Set IO direction register A of the MCP23017 to value. This value determines whether the HAL pins are created as input or as output. On default all pins are created as input.

• -iodirb
  Set IO direction register B of the MCP23017 to value. This value determines whether the HAL pins are created as input or as output. On default all pins are created as input.

• -interval
  Duration of the polling interval the module looks for new values of the HAL pins. Default: 10000000 nanoseconds (10 milliseconds).

PINS

<name>.port-a.gp<N>-out bit in
MCP23017 GPIOA GP pin N is configured as output

<name>.port-b.gp<N>-out bit in
MCP23017 GPIOB GP pin N is configured as output

<name>.port-a.gp<N>-in bit out
MCP23017 GPIOA GP pin N input value if configured as input or pin output value if configured as output

<name>.port-b.gp<N>-in bit out
MCP23017 GPIOA GP pin N input value if configured as input or pin output value if configured as output

<name>.interrupt bit in
On true reads the interrupt registers and GPIO pins from the MCP23017. Usually this pin is connected to the interrupt output pins of the MCP23017. Reading the GPIO clears the MCP23017 interrupt output pin.

<name>.port-a.intf u32 out
MCP23017 interrupt flag register INTFA read by the rising edge of pin interrupt

<name>.port-b.intf u32 out
MCP23017 interrupt flag register INTFB read by the rising edge of pin interrupt

<name>.port-a.intcap u32 out
MCP23017 interrupt capture register INTCAPA read by the rising edge of pin interrupt

<name>.port-b.intcap u32 out
MCP23017 interrupt capture register INTCAPB read by the rising edge of pin interrupt

If the bits of the interrupt registers are needed a bitslice component can be used.

PARAMETERS

Parameters set the MCP23017 configuration registers.

<name>.port-a.ipolarity u32 rw
MCP23017 input polarity register IPOLA

<name>.port-b.ipolarity u32 rw
MCP23017 input polarity register IPOLB

<name>.port-a.gpintenable u32 rw
MCP23017 interrupt-on-change control register GPINTENA

<name>.port-b.gpintenable u32 rw
MCP23017 interrupt-on-change control register GPINTENB

<name>.port-a.defaultvalue u32 rw
MCP23017 default compare register DEFVALA

<name>.port-b.defaultvalue u32 rw
MCP23017 default compare register DEFVALB

<name>.port-a.intcontrol u32 rw
MCP23017 interrupt control register INTCONA

<name>.port-b.intcontrol u32 rw
MCP23017 interrupt control register INTCONB

<name>.port-a.gppullup u32 rw
MCP23017 pull-up resistor configuration register GPPUA

<name>.port-b.gppullup u32 rw
MCP23017 pull-up resistor configuration register GPPUB

<name>.iocon u32 rw
MCP23017 configuration register IOCON
The IOCON register bits BANK and SEQOP are controlled by the component as they are important for correct functionality of the component.

USGAE

Look for a MCP23017 on I2C bus 1 at I2C address 0x20 and configure register IODIRA with 0xaa, name the component ioexpander

loadusr -W hal_mcp23017 -i2cbus 1 -address 0x20 -iodira 0xaa -name ioexpander

AUTHOR

Written by Thomas Gerner

SEE ALSO

bitslice (9)