PCA6416 - 16-bit I2C-bus I/O expander
Description
Library for interfacing NXP PCA6416A 16-bit I2C-bus I/O expander with interrupt output
The PCA6416A is a 16-bit general purpose I/O expander that provides remote I/O expansion for most microcontroller families via the I²C-bus interface. -) I2C interface with communication speed up to 400 kHz -) Two user selectable addresses (chosen by chip pin) -) Built-in level shiffter -) Interrupt output for indicating that an input state has changed
OVERVIEW
PCA6416_Abstract:
This library can be used to handle NXP PCA6416A type 16-bit general purpose I/O expander.
Interfaces:1x I2C 1x IRQ (optional)
The PCA6416A is a 16-bit general purpose I/O expander that provides remote I/O expansion for most microcontroller families via the I²C-bus interface.I2C interface with communication speed up to 400 kHz Two user selectable addresses (chosen by chip pin) Built-in level shifter Interrupt output for indicating that an input state has changed
For more information, see the NXP website
PCA6416_How_to_use:
/* Hardware setup */
const
{
PORT_I2C = 0, // The first I2C interface should be used.
CHIP_ADDR = PCA6416_I2C_ADR0 , // I2C Address of the chip
// (depends on the logic level at the chip's ADDR pin)
}
/* Handles for available sensors */
new hPCA6416[TPCA6416_Handle]; // Handle to manage the PCA6416
main(){
// Inits the I2C interface
catch(rM2M_I2cInit(PORT_I2C, PCA6416_CLOCK, 0));
// Inits PCA6416 (P1_0=Input, all other IOs configured as output with state LOW)
catch(PCA6416_Init(hPCA6416, PORT_I2C, CHIP_ADDR, PCA6416_BITMASK(1,0), 0x0000));
// Sets P1_1=high
catch(PCA6416_Write(hPCA6416, PCA6416_BITMASK(1,1)));
// Reads inputs
new input;
catch(PCA6416_Read(hPCA6416, input));
}
BASIC
PCA6416_CLOCK -
typical I2C clock speed to be used
PCA6416_I2C_ADRx:
Available PCA6416 I2C addresses
PCA6416_I2C_ADR0 - Must be used if ADDR Pin is "Low" (logic 0)
PCA6416_I2C_ADR1 - Must be used if ADDR Pin is "High" (logic 1)
PCA6416_Init(handle[TPCA6416_Handle], i2c, addr, input, output)
Initializes i2c communication with the PCA6416, sets the direction of the I/O pins and sets the outgoing logic levels of the pins defined as outputs
handle : TPCA6416_Handle - Empty device handle for a PCA6416
i2c : s32 - I2C interface where PCA6416 is connected to
The I2C interface must be initialisation before using rM2M_I2cInit().
addr : s32 - I2C Address of the chip (depends on the logic level at the chip's ADDR pin)
Use only the addresses specified under PCA6416_I2C_ADRx
input : s32 - Direction of the I/O pins (Bitmask, Bit0 = P0.0, ..., Bit7 = P0.7, Bit8 = P1.0, ..., Bit15 = P1.7)
0 - Output
1 - Input
output : s32 - Outgoing logic levels of the pins defined as outputs (Bitmask, Bit0 = P0.0, ..., Bit7 = P0.7, Bit8 = P1.0, ..., Bit15 = P1.7)
0 - "Low"
1 - "High"
Bit values have no effect on pins defined as inputs.
returns : s32
OK - If successful
ERROR - If an error occurs
PCA6416_BITMASK(port, pin)
Helper macro to convert port and pin to a bitmask
port : s32 - Port number 0-1
pin : s32 - Pin number 0-7
returns : s32 - 16-bit bitmask
PCA6416_Read(handle[TPCA6416_Handle], &val)
Read PCA6416 Inputs
handle : TPCA6416_Handle - Device handle of a specific PCA6416 (Initialized by PCA6416_Init() )
val - Buffer for storing the read input values (Bitmask, Bit0 = P0.0, ..., Bit7 = P0.7, Bit8 = P1.0, ..., Bit15 = P1.7)
1 - "High"
0 - "Low"
The Polarity inversion registers allow polarity inversion of pins defined as inputs. Polarity inversion is not enabled by this library. However, you can use the PCA6416_Com() function to enable polarity inversion.
returns : s32
OK - If successful
ERROR - If an error occurs
PCA6416_Write(handle[TPCA6416_Handle], value)
Writes the logic levels to be set for the outputs pins to the output port register of the PCA6416
handle : TPCA6416_Handle - Device handle of a specific PCA6416 (Initialized by PCA6416_Init() )
value - Logic levels to be set (Bitmask, Bit0 = P0.0, ..., Bit7 = P0.7, Bit8 = P1.0, ..., Bit15 = P1.7)
0 - "Low"
1 - "High"
Bit values have no effect on pins defined as inputs.
returns : s32
OK - If successful
ERROR - If an error occurs
PCA6416_IrqInit(irq, callback)
Enable IRQ handling
irq : s32 - Number of the interruptible pin (ranging from 0 for the first IRQ pin of the device up to WATCH_COUNT-1)
callback : TonWatch - Function that should be executed in the event of an interrupt
Type of function: #callback func(pinstate);
The interrupt is generated (falling edge on the PCA6416 INT pin) if any of the inputs changes. It is recommended to use PCA6416_Read within the
callback function to get the current input state.
PCA6416_IrqClose(irq)
Disable IRQ handling
irq : s32 - Number of the interruptible pin (ranging from 0 for the first IRQ pin of the device up to WATCH_COUNT-1)
EXPERT
PCA6416_CLOCK_MAX -
absolute maximum I2C clock speed
PCA6416_CMD_x:
Available commands/registers (Command | R/W | Default | Description)
PCA6416_CMD_INPUT_PORT_0 - 0x00 | r | undefined | Input port 0
PCA6416_CMD_INPUT_PORT_1 - 0x01 | r | undefined | Input port 1
PCA6416_CMD_OUTPUT_PORT_0 - 0x02 | r/w | 0xFF | Output port 0
PCA6416_CMD_OUTPUT_PORT_1 - 0x03 | r/w | 0xFF | Output port 1
PCA6416_CMD_POLARITY_INV_0 - 0x04 | r/w | 0x00 | Polarity Inversion port 0 (Only affects the input register)
PCA6416_CMD_POLARITY_INV_1 - 0x05 | r/w | 0x00 | Polarity Inversion port 1 (Only affects the input register)
PCA6416_CMD_CONFIG_PORT_0 - 0x06 | r/w | 0xFF | Configuration port 0
PCA6416_CMD_CONFIG_PORT_1 - 0x07 | r/w | 0xFF | Configuration port 1
PCA6416_Com(handle[TPCA6416_Handle], aData{}, writelen, readlen)
Performs raw PCA6416 read/write access. Data is first of all sent and data is then received.
handle : TPCA6416_Handle - Device handle of a specific PCA6416 (Initialized by PCA6416_Init() )
aData : {} - Array in which the data to be sent must initially be saved. Once the data has been sent, the array is used as a memory for the data to be received.
writelen : s32 - Number of bytes to be sent
readlen : s32 - Number of bytes to be received
returns : s32
OK - if successful
ERROR - if one of the following errors occurs
Access to PCA6416 is always started by sending one byte command code (see PCA6416_CMD_x definitions) followed by one byte read/write data.
Please see datasheet for more information.
DEBUG
PCA6416_Debug_Config:
To configure debug mode add the following macro to the main.dde file.
/**
* Use this macro to configure the debug mode:
*
* 0: No debugging
* >0: Issues the following information via the console:
* -) I2C address used to access the PCA6416
* -) When initializing: direction of the I/O pins and Outgoing logic
* levels of the pins defined as outputs
* -) The content of the input port registers is output when calling PCA6416_Read
* -) The logic levels to be set for the outputs are output when calling PCA6416_Write
*
*/
#define PCA6416_DEBUG 0