#include <MAX6956.h>

Public Member Functions
	MAX6956 ()

	MAX6956 (uint8_t address)

void	initialize ()

bool	testConnection ()

void	reset ()

uint8_t	getConfigReg ()

void	setConfigReg (uint8_t config)

bool	getPower ()

void	togglePower ()

void	setPower (bool power)

bool	getEnableIndividualCurrent ()

void	setEnableIndividualCurrent (bool global)

bool	getEnableTransitionDetection ()

void	setEnableTransitionDetection (bool transition)

uint8_t	getGlobalCurrent ()

void	setGlobalCurrent (uint8_t current)

bool	getTestMode ()

void	setTestMode (bool test)

uint8_t	getInputMask ()

void	setInputMask (uint8_t mask)

void	configPort (uint8_t port, uint8_t portConfig)

void	configPorts (uint8_t lower, uint8_t upper, uint8_t portConfig)

void	configAllPorts (uint8_t portConfig)

void	setPortLevel (uint8_t port, uint8_t power)
	0 = off, 1-15 brightness levels. More...

void	setPortCurrent (uint8_t port, uint8_t power)
	0-15 brightness levels. More...

void	setAllPortsCurrent (uint8_t power)
	0-15, 0 = min brightness (not off) 15 = max More...

void	enableAllPorts ()

void	disableAllPorts ()

Data Fields
uint8_t	portsConfig [5]

uint8_t	portsStatus [3]

Private Attributes
uint8_t	devAddr
	Holds the current device address. More...

uint8_t	buffer [1]
	Buffer for reading data from the device. More...

uint8_t	portConfig
	Holder for port config bit pair. More...

uint8_t	portCurrentRA
	Holder for port current register. More...

uint8_t	portCurrentBit
	Holder for the current bit offset. More...

uint8_t	psArrayIndex
	array index More...

uint8_t	psBitPosition
	bit position More...

Detailed Description

A library for controlling the MAX6956 using i2C.

The MAX6956 compact, serial-interfaced LED display driver/I/O expander provide microprocessors with up to 28 ports. Each port is individually user configurable to either a logic input, logic output, or common-anode (CA) LED constant-current segment driver. Each port configured as an LED segment driver behaves as a digitally controlled constant-current sink, with 16 equal current steps from 1.5mA to 24mA. The LED drivers are suitable for both discrete LEDs and CA numeric and alphanumeric LED digits.

Each port configured as a general-purpose I/O (GPIO) can be either a push-pull logic output capable of sink- ing 10mA and sourcing 4.5mA, or a Schmitt logic input with optional internal pullup. Seven ports feature config- urable transition detection logic, which generates an interrupt upon change of port logic level. The MAX6956 is controlled through an I2C-compatible 2-wire serial interface, and uses four-level logic to allow 16 I 2C addresses from only 2 select pins.

The MAX6956AAX and MAX6956ATL have 28 ports and are available in 36-pin SSOP and 40-pin thin QFN packages, respectively. The MAX6956AAI and MAX6956ANI have 20 ports and are available in 28-pin SSOP and 28-pin DIP packages, respectively.

For an SPI-interfaced version, refer to the MAX6957 data sheet. For a lower cost pin-compatible port expander without the constant-current LED drive capa- bility, refer to the MAX7300 data sheet.

400kbps I2C-Compatible Serial Interface
2.5V to 5.5V Operation
-40°C to +125°C Temperature Range
20 or 28 I/O Ports, Each Configurable as
Constant-Current LED Driver
Push-Pull Logic Output
Schmitt Logic Input
Schmitt Logic Input with Internal Pullup
11μA (max) Shutdown Current
16-Step Individually Programmable Current
Control for Each LED
Logic Transition Detection for Seven I/O Ports

Definition at line 456 of file MAX6956.h.

Constructor & Destructor Documentation

MAX6956::MAX6956 ( )

Default constructor, uses default I2C address.

See Also: MAX6956_DEFAULT_ADDRESS

Definition at line 40 of file MAX6956.cpp.

MAX6956::MAX6956 ( uint8_t address )

Specific address constructor.

Parameters

address I2C address

See Also: MAX6956_DEFAULT_ADDRESS; MAX6956_ADDRESS

Definition at line 49 of file MAX6956.cpp.

Member Function Documentation

void MAX6956::configAllPorts ( uint8_t portConfig )

Configure all ports the same

Parameters

portConfig Valid options are: MAX6956_OUTPUT_LED, MAX6956_OUTPUT_GPIO, MAX6956_INPUT_WO_PULL, MAX6956_INPUT_W_PULL

See Also: MAX6956_OUTPUT_LED; MAX6956_OUTPUT_GPIO; MAX6956_INPUT_WO_PULL; MAX6956_INPUT_W_PULL

Definition at line 332 of file MAX6956.cpp.

void MAX6956::configPort	(	uint8_t	port,
		uint8_t	portConfig
	)

Takes an INDIVIDUAL port register address (MAX6956_RA_PORT12, ect)
and configures it as: MAX6956_OUTPUT_LED, MAX6956_OUTPUT_GPIO,
MAX6956_INPUT_WO_PULL, or MAX6956_INPUT_W_PULL

Port registers

Addr.	Name
0x09	MAX6956_RA_CONFIG_P7P6P5P4
0x0A	MAX6956_RA_CONFIG_P11P10P9P8
0x0B	MAX6956_RA_CONFIG_P15P14P13P12
0x0C	MAX6956_RA_CONFIG_P19P18P17P16
0x0D	MAX6956_RA_CONFIG_P23P22P21P20
0x0E	MAX6956_RA_CONFIG_P27P26P25P24
0x0F	MAX6956_RA_CONFIG_P31P30P29P28

Num	Dec	Hex	Prt	Port Status Array	Ports Config Array
00	44	0x2C	P12	portsStatus[0][0]	portsConfig[0][1-0]
01	45	0x2D	P13	portsStatus[0][1]	portsConfig[0][3-2]
02	46	0x2E	P14	portsStatus[0][2]	portsConfig[0][5-4]
03	47	0x2F	P15	portsStatus[0][3]	portsConfig[0][7-6]
04	48	0x30	P16	portsStatus[0][4]	portsConfig[1][1-0]
05	49	0x31	P17	portsStatus[0][5]	portsConfig[1][3-2]
06	50	0x32	P18	portsStatus[0][6]	portsConfig[1][5-4]
07	51	0x33	P19	portsStatus[0][7]	portsConfig[1][7-6]
08	52	0x34	P20	portsStatus[1][0]	portsConfig[2][1-0]
09	53	0x35	P21	portsStatus[1][1]	portsConfig[2][3-2]
10	54	0x36	P22	portsStatus[1][2]	portsConfig[2][5-4]
11	55	0x37	P23	portsStatus[1][3]	portsConfig[2][7-6]
12	56	0x38	P24	portsStatus[1][4]	portsConfig[3][1-0]
13	57	0x39	P25	portsStatus[1][5]	portsConfig[3][3-2]
14	58	0x3A	P26	portsStatus[1][6]	portsConfig[3][5-4]
15	59	0x3B	P27	portsStatus[1][7]	portsConfig[3][7-6]
16	60	0x3C	P28	portsStatus[2][0]	portsConfig[4][1-0]
17	61	0x3D	P29	portsStatus[2][1]	portsConfig[4][3-2]
18	62	0x3E	P30	portsStatus[2][2]	portsConfig[4][5-4]
19	63	0x3F	P31	portsStatus[2][3]	portsConfig[4][7-6]

Parameters

port	Port register address (MAX6956_RA_PORT12, ect)
portConfig	Valid options are: MAX6956_OUTPUT_LED, MAX6956_OUTPUT_GPIO, MAX6956_INPUT_WO_PULL, MAX6956_INPUT_W_PULL

Definition at line 265 of file MAX6956.cpp.

void MAX6956::configPorts	(	uint8_t	lower,
		uint8_t	upper,
		uint8_t	portConfig
	)

Configure consecutive range of ports

Parameters

lower	Lower port register address (MAX6956_RA_PORT12, ect)
upper	Upper port register address (MAX6956_RA_PORT12, ect)
portConfig	Valid options are: MAX6956_OUTPUT_LED, MAX6956_OUTPUT_GPIO, MAX6956_INPUT_WO_PULL, MAX6956_INPUT_W_PULL

See Also: MAX6956_OUTPUT_LED; MAX6956_OUTPUT_GPIO; MAX6956_INPUT_WO_PULL; MAX6956_INPUT_W_PULL

Definition at line 285 of file MAX6956.cpp.

void MAX6956::disableAllPorts ( )

Write 0's to all port registers.

Definition at line 463 of file MAX6956.cpp.

void MAX6956::enableAllPorts ( )

Write 1's to all port registers. This enables ports set as outputs and they will always have some brightness, port must be disabled to turn off completely.

Definition at line 453 of file MAX6956.cpp.

uint8_t MAX6956::getConfigReg ( )

Config register

Returns: uint8_t value of register

See Also: MAX6956_RA_CONFIGURATION

Definition at line 94 of file MAX6956.cpp.

bool MAX6956::getEnableIndividualCurrent ( )

Get transition detection configuration bit

Returns: Boolean value if global current is enabled or not

See Also: MAX6956_RA_CONFIGURATION

Definition at line 134 of file MAX6956.cpp.

bool MAX6956::getEnableTransitionDetection ( )

Get transition detection configuration bit

Returns: Boolean value if transition detection is enabled or not

See Also: MAX6956_RA_CONFIGURATION

Definition at line 152 of file MAX6956.cpp.

uint8_t MAX6956::getGlobalCurrent ( )

Get global current

Returns: uint8_t value of register

See Also: MAX6956_RA_GLOBAL_CURRENT

Definition at line 171 of file MAX6956.cpp.

uint8_t MAX6956::getInputMask ( )

Get the input mask to see which ports have changed. MSB is cleared after every read.

Returns: uint8_t value of register

See Also: MAX6956_RA_TRANSITION_DETECT

Definition at line 205 of file MAX6956.cpp.

bool MAX6956::getPower ( )

Get power configuration bit

Returns: Boolean value if power is enabled or not

See Also: MAX6956_RA_CONFIGURATION

Definition at line 110 of file MAX6956.cpp.

bool MAX6956::getTestMode ( )

Returns true if test mode is enabled.

Returns: uint8_t value of register

See Also: MAX6956_RA_DISPLAY_TEST

Definition at line 188 of file MAX6956.cpp.

void MAX6956::initialize ( )

Power on and prepare for general usage.

The 28-pin MAX6956ANI and MAX6956AAI make only 20 ports available, P12 to P31.

The eight unused ports should be configured as outputs on power-up by writing 0x55 to registers 0x09 and 0x0A. If this is not done,the eight unused ports remain as unconnected inputs and quiescent supply current rises, although there is no damage to the part.

Definition at line 54 of file MAX6956.cpp.

void MAX6956::reset ( )

Set registers back to Power-up Configuration

Definition at line 80 of file MAX6956.cpp.

void MAX6956::setAllPortsCurrent ( uint8_t power )

0-15, 0 = min brightness (not off) 15 = max

Set ALL port current registers (MAX6956_RA_PORT12, ect) to the SAME power level 0-15. 0 is off, 15 is max brightness.

Parameters

power 0 is min, 15 is max brightness.

Definition at line 444 of file MAX6956.cpp.

void MAX6956::setConfigReg ( uint8_t config )

Set config register

Parameters

config uint8_t value to set register

See Also: MAX6956_RA_CONFIGURATION

Definition at line 102 of file MAX6956.cpp.

void MAX6956::setEnableIndividualCurrent ( bool global )

Enable or disable global current

Parameters

global Boolean value, true enables, false disables individual current

See Also: MAX6956_RA_CONFIGURATION; getGlobalCurrent(); setGlobalCurrent()

Definition at line 144 of file MAX6956.cpp.

void MAX6956::setEnableTransitionDetection ( bool transition )

Enable or disable transition detection. Must be reset after every mask read.

Parameters

transition Boolean value, true enables, false disables transition detection

See Also: MAX6956_RA_CONFIGURATION; getInputMask(); setInputMask()

Definition at line 162 of file MAX6956.cpp.

void MAX6956::setGlobalCurrent ( uint8_t current )

Set current globally

Parameters

current uint8_t 0-15, 0 = min, 15 = max brightness

See Also: MAX6956_RA_GLOBAL_CURRENT

Definition at line 179 of file MAX6956.cpp.

void MAX6956::setInputMask ( uint8_t mask )

Set the input mask for which ports to monitor with transition detection

Parameters

mask	8 bit value. MSB is ignored.

See Also: MAX6956_RA_TRANSITION_DETECT

Definition at line 214 of file MAX6956.cpp.

void MAX6956::setPortCurrent	(	uint8_t	port,
		uint8_t	power
	)

0-15 brightness levels.

Takes an INDIVIDUAL port register address (MAX6956_RA_PORT12, ect)

and sets it to a power level 0-15. 0 is min, 15 is max brightness.

Parameters

port	Port register address (MAX6956_RA_PORT12, ect)
power	0 is min, 15 is max brightness.

Definition at line 404 of file MAX6956.cpp.

void MAX6956::setPortLevel	(	uint8_t	port,
		uint8_t	power
	)

0 = off, 1-15 brightness levels.

Takes an individual port register address (MAX6956_RA_PORT12, ect)

and sets it to a power scale where 0 = off.

Parameters

port	Port register address (MAX6956_RA_PORT12, ect)
power	0 is off, 15 is max brightness.

Definition at line 346 of file MAX6956.cpp.

void MAX6956::setPower ( bool power )

Enable or disable power

Parameters

power Boolean value, true enables, false disables power

See Also: MAX6956_RA_CONFIGURATION

Definition at line 118 of file MAX6956.cpp.

void MAX6956::setTestMode ( bool test )

Enable or disable test mode

Parameters

test	Boolean, true enables, false disables

See Also: MAX6956_RA_DISPLAY_TEST

Definition at line 196 of file MAX6956.cpp.

bool MAX6956::testConnection ( )

Verify the I2C connection. Make sure the device is connected and responds as expected.

Returns: True if connection is valid, false otherwise

Definition at line 72 of file MAX6956.cpp.

void MAX6956::togglePower ( )

Toggle power

See Also: MAX6956_RA_CONFIGURATION

Definition at line 124 of file MAX6956.cpp.

Field Documentation

uint8_t MAX6956::buffer[1]

private

Buffer for reading data from the device.

Definition at line 556 of file MAX6956.h.

uint8_t MAX6956::devAddr

private

Holds the current device address.

Definition at line 555 of file MAX6956.h.

uint8_t MAX6956::portConfig

private

Holder for port config bit pair.

Definition at line 557 of file MAX6956.h.

uint8_t MAX6956::portCurrentBit

private

Holder for the current bit offset.

Definition at line 559 of file MAX6956.h.

uint8_t MAX6956::portCurrentRA

private

Holder for port current register.

Definition at line 558 of file MAX6956.h.

uint8_t MAX6956::portsConfig[5]

Array that mirrors the configuration of all the ports.

P12 = portsConfig[0][1-0] P13 = portsConfig[0][3-2] P14 = portsConfig[0][5-4] P15 = portsConfig[0][7-6] P16 = portsConfig[1][1-0] P17 = portsConfig[1][3-2] P18 = portsConfig[1][5-4] P19 = portsConfig[1][7-6] P20 = portsConfig[2][1-0] P21 = portsConfig[2][3-2] P22 = portsConfig[2][5-4] P23 = portsConfig[2][7-6] P24 = portsConfig[3][1-0] P25 = portsConfig[3][3-2] P26 = portsConfig[3][5-4] P27 = portsConfig[3][7-6] P28 = portsConfig[4][1-0] P29 = portsConfig[4][3-2] P30 = portsConfig[4][5-4] P31 = portsConfig[4][7-6]

Definition at line 527 of file MAX6956.h.

uint8_t MAX6956::portsStatus[3]

Array that mirrors the on/off status of all the ports.

P12 = portsStatus[0][0] P13 = portsStatus[0][1] P14 = portsStatus[0][2] P15 = portsStatus[0][3] P16 = portsStatus[0][4] P17 = portsStatus[0][5] P18 = portsStatus[0][6] P19 = portsStatus[0][7] P20 = portsStatus[1][0] P21 = portsStatus[1][1] P22 = portsStatus[1][2] P23 = portsStatus[1][3] P24 = portsStatus[1][4] P25 = portsStatus[1][5] P26 = portsStatus[1][6] P27 = portsStatus[1][7] P28 = portsStatus[2][0] P29 = portsStatus[2][1] P30 = portsStatus[2][2] P31 = portsStatus[2][3]

Definition at line 552 of file MAX6956.h.

uint8_t MAX6956::psArrayIndex

private

array index

Definition at line 560 of file MAX6956.h.

uint8_t MAX6956::psBitPosition

private

bit position

Definition at line 561 of file MAX6956.h.

The documentation for this class was generated from the following files:

Public Member Functions

Data Fields

Private Attributes

Detailed Description

Constructor & Destructor Documentation

Member Function Documentation

Port registers

Field Documentation