The following attributes are available for all devices supporting an ARINC 429 interface.

Common attributes

Speed

The KMXF_A429_SPEED attribute holds the actual channel speed, in bits per second.
For IPM-429 this attribute is read-only, speed is selected with KMXF_A429_SPEED_SELECT attribute.
The supported range is:

Module	Range (bps)	Default (bps)
MXF_MODULE_A429_EH	4000 - 125000	12500
MXF_MODULE_MULTI_EH	4000 - 800000	12500
MXF_MODULE_MULTI	4000 - 800000	12500
MXF_MODULE_A429E	4000 - 125000	12500
MXF_MODULE_FLEX429	4000 - 125000	12500

Parity

The KMXF_A429_PARITY attribute holds the channel parity setting.

For a transmitter channel, it represents the parity bit to be generated (if any). For a receiver channel, it is the expected received word parity.

The supported values are:

Transmitter Channel:

Constant	Value
VMXF_A429_PARITY_EVEN	Channel has even parity.
VMXF_A429_PARITY_ODD	Channel has odd parity. (default)
VMXF_A429_PARITY_NONE	Channel parity is not defined. Parity bit is transmitted with the value set by the application.

Receiver Channel:

Constant	Value
VMXF_A429_PARITY_EVEN	Channel has even parity.
VMXF_A429_PARITY_ODD	Channel has odd parity. (default)
VMXF_A429_PARITY_NONE	The module does not check the received data for parity error.

When a parity error is detected in reception, the control field of the MXF_A429_DATAREC or MXF_A429_SAMPREC is set to MXF_A429_RX_REC_CTRL_PARITY_ERROR;

Word Size

The KMXF_A429_WORDSIZE attribute holds the ARINC 429 word size, in number of bits, for the channel.

The supported values are:

Constant	Value (bits)
VMXF_A429_WORDSIZE_25	25
VMXF_A429_WORDSIZE_32	32 (default)

Inter-Word Gap

The KMXF_A429_GAP attribute holds the minimum inter-word gap value for a channel.

Transmitter Channel:

This attribute is used to set/get the gap length time between transmission of two words with a resolution of a quarter of a bit.
On IPM-429 and IPM-MULTI, this attribute is not available. Use KMXF_A429_GAP_SELECT instead.

The supported range is:

Range	Value (1/4 bit)
Minimum	0
Maximum	63

Default value: 16 (4.0 bits)

Receiver Channel:

This attribute is used to set/get the minimum gap length time between reception of two words with a resolution of a quarter of a bit. If second word is received before this gap value, the word is discarded and MXF_RX_STATUS_GAP_LENGTH status bit is set.
On IPM-429 and IPM-MULTI, this attribute is not available.

The supported range is:

Range	Value (1/4 bit)
Minimum	6
Maximum	63

Default value: 14 (3.50 bits)

TX Gap Select

The KMXF_A429_GAP_SELECT selects the minimum transmitter gap value. This attribute specifies if the channel uses the default gap value, (4 bits) or a custom gap value (set by KMXF_A429_MODULE_TX_CUSTOM_GAP attribute).
This attribute is only available with IPM-429 and IPM-MULTI. For others, see KMXF_A429_GAP.

The supported values are:

Constant	Value
VMXF_A429_GAP_DEFAULT	Select default gap (default)
VMXF_A429_CUSTOM_GAP	Select value defined by KMXF_A429_MODULE_TX_CUSTOM_GAP

Note: Four bits are the minimum defined by the ARINC 429 specifications.

TX Custom Gap

The KMXF_A429_MODULE_TX_CUSTOM_GAP attribute defines the value of the custom gap.

This attribute holds the custom gap value for the module. This value applies to all transmitter channels on the module that have selected the custom gap.
The gap length is the time between two words with a resolution of a quarter of a bit.
This attribute is only available with IPM-429 and IPM-MULTI. For others, see KMXF_A429_GAP.

The supported range is:

Range	Value (1/4 bit)
Minimum	0
Maximum	63

Default value: 16 (4 bits)

Loopback Mode

The KMXF_A429_TX_RX_TEST_LB attribute holds the TX-to-RX loopback state for the receiver channel. When the loopback mode is enabled, the received data comes from the corresponding transmitter channel instead of the normal behavior where the received data comes from the receiver line interface. This feature is intended for a demo application or for test purposes. When enabled, the module’s first RX channel receives data transmitted on the first TX channel; the second RX receives data from the second TX, and so on. Transmissions are still sent on the TX line when loopback mode is enabled.

The supported values are:

Constant	Value
VMXF_DISABLE	Disable loopback (default)
VMXF_ENABLE	Enable loopback

TX Slew Rate Selection

The KMXF_A429_TX_SLEW_RATE_SELECTION attribute defines the TX slew rate selection. MX Foundation automatically calculates the default slew rate based on the channel speed for non-parametric IO-429-EH channels and IO-FLEX429 channels and on channel speed, high and low differential voltage values for IO-MULTI-EH, IPM-MULTI and parametric IO-429-EH channels. When the default option is selected, the KMXF_A429_TX_SLEW_RATE attribute will be read only. Otherwise, the custom option allows specifying the slew rate with the KMXF_A429_TX_SLEW_RATE attribute. On IO-MULTI-EH, IPM-MULTI and parametric IO-429-EH channels, to modify this attribute value, the KMXF_A429_ELECTRICAL_SELECTION attribute must be set to custom.

Constant	Value
VMXF_A429EH_MULTI_TX_SLEW_RATE_SELECT_DEFAULT	Select default slew rate parameter (default)
VMXF_A429EH_MULTI_TX_SLEW_RATE_SELECT_CUSTOM	Select custom slew rate parameter

TX Signal Slew Rate

The KMXF_A429_TX_SLEW_RATE attribute defines the TX signal slew rate. MX Foundation automatically calculates the default slew rate based on the channel speed for non-parametric IO-429-EH channels and IO-FLEX429 channels and on channel speed, high and low differential voltage values for IO-MULTI-EH, IPM-MULTI and parametric IO-429-EH channels. When the default option is selected, the KMXF_A429_TX_SLEW_RATE attribute will be read only. Otherwise, the custom option of the KMXF_A429_TX_SLEW_RATE_SELECTION attribute allows specifying the slew rate with this attribute. This is a floating point attribute for IO-MULTI-EH, IPM-MULTI and parametric IO-429-EH channels.

The supported values for non-parametric IO-429-EH channels and IO-FLEX429 channels are:

Constant	Value
VMXF_A429EH_TX_SLEW_RATE_LOW	Select low slew rate value
VMXF_A429EH_TX_SLEW_RATE_HIGH	Select high slew rate value

The supported range for IO-MULTI-EH channels is:

Range	Value (nsec/volt)
Minimum	2.0
Maximum	13429.5

Value will be rounded to closest supported step. Formula for supported steps is: (204800/1.22) / (n*3.125) with 4 ≤ n ≤ 26860 in step of 4.

Default value: 2685.90

The supported range for parametric IO-429-EH channels (FlexMobile 429+) is:

Range	Value (nsec/volt)
Minimum	20
Maximum	13429.5

Value will be rounded to closest supported step. Formula for supported steps is: (204800/1.22) / (n*3.125) with 4 ≤ n ≤ 26860 in step of 4.

Default value: 2685.90

The supported range for MXF_MODULE_MULTI is:

Range	Value (nsec/volt)
Minimum	25.0
Maximum	25600

Value will be rounded to closest supported step. Formula for supported steps is: 102400 / n with 4096 ≤ n ≤ 51200 in step of 4.

Default value: 2560

Time tag usage

The KMXF_A429_MODULE_RX_TIMETAG_ENABLE attribute defines the RX time tag enable state. When the time tag reception is disabled, the timeTag field of MXF_A429_DATAREC and MXF_A429_SAMPREC will always be 0. Also, the rate field of MXF_A429_SAMPREC will always be 0 as time tags are needed to compute it. Disabling the time tag can result in a small gain in performance because less data are transferred between the module and the reception buffer.
Not available on IO-FLEX429.

Constant	Value
VMXF_DISABLE	Disable time tag reception
VMXF_ENABLE	Enable time tag reception (default)

RX FIFO Aging Timeout

The KMXF_A429_MODULE_RX_FIFO_AGING attribute defines the RX FIFO aging timeout value for the module. This value applies to all receiver channels on the module. Aging timeout is the duration that a received word can wait in the FIFO before an interrupt is generated. It defines the longest delay that a received word can wait in the hardware FIFO before a receive interrupt is generated. The attribute value resolution is based on the timebase resolution. A RX FIFO Aging Timeout value of 0 disables the aging timeout. The attribute value is rounded down to step of 512 microseconds for IO-429-EH module and step of 128 microseconds for IO-MULTI-EH module.

The supported range is:

Module	Range (microsecond)	Default (microsecond)	Note
MXF_MODULE_A429_EH	0 - 7680	7680	Value is rounded down to step of 512 microseconds
MXF_MODULE_MULTI_EH	0 - 32640	8192	Value is rounded down to step of 128 microseconds
MXF_MODULE_MULTI	0 - 32640	8192	Value is rounded down to step of 128 microseconds
MXF_MODULE_A429E	0 - 7680	7680	Value is rounded down to step of 512 microseconds
MXF_MODULE_FLEX429	0 - 25000	8000	Value is rounded down to step of 100 microseconds

Note: MX Foundation takes care of initializing this attribute using the optimal value. It is not recommended to change to this attribute unless told to do so by a MAX Technologies' support engineer.

RX FIFO Almost Full Threshold

The KMXF_A429_MODULE_RX_FIFO_AF attribute holds the RX FIFO almost full threshold for the module. This value applies to all receiver channels on the module. This attribute value determines the number of received 16-bit words that are accumulated in the receive hardware FIFO before an interrupt is generated. The receiver engine reads the FIFO when it is almost full or an aging timeout occurred.

The supported range is:

Module	Range	Default
MXF_MODULE_A429_EH	1 - 255 (16-bit word)	48
MXF_MODULE_MULTI_EH	1 - 255 (16-bit word)	32
MXF_MODULE_MULTI	1 - 255 (16-bit word)	16
MXF_MODULE_A429E	1 - 32 (64-bit word)	6
MXF_MODULE_FLEX429	1 - 511 (A429 block)	128

Note: MX Foundation takes care of initializing this attribute using the optimal value. It is not recommended to change to this attribute unless told to do so by a MAX Technologies' support engineer.

TX FIFO Almost Full Threshold

The KMXF_A429_MODULE_TX_FIFO_AF attribute holds the TX FIFO almost full threshold for the module. This value applies to all transmitter channels on the module. This attribute value determines the number of transmit 16-bit words that are to be queued in the transmit hardware FIFO. The transmit interrupt is automatically cleared once this threshold is reached.

The supported range is:

Module	Range	Default
MXF_MODULE_A429_EH	2 - 255 (16-bit word)	48
MXF_MODULE_MULTI_EH	2 - 255 (16-bit word)	128
MXF_MODULE_MULTI	2 - 255 (16-bit word)	128
MXF_MODULE_A429E	2 - 32 (64-bit word)	6
MXF_MODULE_FLEX429	2 - 127 (A429 block)	32

Note: MX Foundation takes care of initializing this attribute using the optimal value. It is not recommended to change to this attribute unless told to do so by a MAX Technologies' support engineer.

TX FIFO Almost Empty Threshold

The KMXF_A429_MODULE_TX_FIFO_AE attribute holds the TX FIFO almost empty threshold for the module. This value applies to all transmitter channels on the module. The attribute value determines when the transmit interrupt is generated. The transmit interrupt is generated whenever the number of 16-bit words remaining in the transmit hardware FIFO is less or equal to the value specified by this attribute. The software embedded process is then able to react and fill in the transmit FIFO.

The supported range is:

Module	Range	Default
MXF_MODULE_A429_EH	1 - 254 (16-bit word)	32
MXF_MODULE_MULTI_EH	1 - 254 (16-bit word)	64
MXF_MODULE_MULTI	1 - 254 (16-bit word)	64
MXF_MODULE_A429E	1 - 31 (64-bit word)	5
MXF_MODULE_FLEX429	1 - 127 (A429 block)	8

Note: MX Foundation takes care of initializing this attribute using the optimal value. It is not recommended to change to this attribute unless told to do so by a MAX Technologies' support engineer.

Tx Port Enable

The KMXF_A429_TX_PORT_ENABLE attribute defines the enable state of the transmitter.

This attribute is only available on bidirectionnal channel. By default, the port is in receiver mode, set this attribute to VMXF_ENABLED to enable the transmitter.

The supported values are:

Constant	Value
VMXF_DISABLED	The transmitter is disabled (default)
VMXF_ENABLED	The transmitter is enabled

Module Options

The KMXF_A429_MODULE_OPTIONS attribute defines the options supported on the module.

The supported values are:

Constant	Value
VMXF_A429_MODULE_OPTIONS_BIDIRECTIONAL	The module has bidirectionnal channel (see KMXF_A429_TX_PORT_ENABLE)

IPM-429 attributes

The following ARINC 429 channel attributes are available only for MXF_MODULE_A429E:

High Speed

The KMXF_A429_MODULE_HIGH_SPEED attribute holds the module high-speed value, in bit per second. The module supports two concurrent speeds, a high and a low speed. The speed assigned to this attribute is the effective channel speed of every channel that has been configured as high-speed channel (i.e. the channel that has its KMXF_A429_SPEED_SELECT attribute set to VMXF_A429_SPEED_SELECT_HIGH).

The supported range is:

Range	Value (bps)
Minimum	4000
Maximum	125000

Default value: 100000 bps

Low Speed

The KMXF_A429_MODULE_LOW_SPEED attribute holds the module low-speed value, in bit per second. The module supports two concurrent speeds, a high and a low speed. The speed assigned to this attribute is the effective channel speed of every channel that has been configured as low-speed channel (i.e. the channel that has its KMXF_A429_SPEED_SELECT attribute set to VMXF_A429_SPEED_SELECT_LOW).

The supported range is:

Range	Value (bps)
Minimum	4000
Maximum	25000

Default value: 12500 bps

Speed Select

The KMXF_A429_SPEED_SELECT attribute defines which speed selection (high or low) is currently in use on the channel.

The supported values are:

Constant	Value
VMXF_A429_SPEED_SELECT_LOW	Select low-speed (default)
VMXF_A429_SPEED_SELECT_HIGH	Select high-speed

Parametric attributes

The following ARINC 429 attributes are available only for parametric channel (IO-MULTI and FMOB-A844-P) device.

Electrical Selection

The KMXF_A429_ELECTRICAL_SELECTION attribute holds the actual channel electrical selection. When the electrical selection is set to default, all electrical attributes below are set to a default value and are read only. To modify any of these attributes, set electrical selection to custom.

Constant	Value
VMXF_A429EH_MULTI_ELECTRICAL_SELECT_DEFAULT	Select default electrical parameters (default)
VMXF_A429EH_MULTI_ELECTRICAL_SELECT_CUSTOM	Select custom electrical parameters

TX Differential Voltage High

The KMXF_A429_TX_DIFF_VOLTAGE_HIGH attribute defines the high TX differential voltage value for IO-MULTI-EH, IPM-MULTI and parametric IO-429-EH Tx channels. This is a floating point attribute. To modify this attribute value, the KMXF_A429_ELECTRICAL_SELECTION attribute must be set to custom.

The supported range is:

Device	Range (V)
FlexMobile	-6.50 – +6.50
IPM-MULTI	-9.16 – +9.16
MXF_MODULE_MULTI_EH	see table below

Default value: +5.0 V

MXF_MODULE_MULTI_EH

Device Type	Revision	MXF Version	Range (Volt)
FlexMulti 629	Up to 2.4	Up to 4.2.5	-5.0 – +5.0
		4.3.0 to 4.4.1	-6.0 – +6.0
		4.4.2 and later	-6.1 – +6.1
	2.5 and later	Up to 4.2.5	-5.0 – +5.0
	2.5 and later	4.3.0 and later	-6.5 – +6.5
FlexMulti 1553	Up to 3.2	Up to 4.2.5	-5.0 – +5.0
		4.3.0 to 4.4.1	-6.0 – +6.0
		4.4.2 and later	-6.1 – +6.1
	3.3 and later	Up to 4.2.5	-5.0 – +5.0
	3.3 and later	4.3.0 and later	-6.5 – +6.5
FlexMulti 429 FlexMulti 664 FlexMulti	Up to 3.0	Up to 4.2.5	-5.0 – +5.0
		4.3.0 to 4.4.1	-6.0 – +6.0
		4.4.2 and later	-6.1 – +6.1
	3.1 and later	Up to 4.2.5	-5.0 – +5.0
	3.1 and later	4.3.0 and later	-6.5 – +6.5

TX Differential Voltage Low

The KMXF_A429_TX_DIFF_VOLTAGE_LOW attribute defines the low TX differential voltage value for IO-MULTI-EH, IPM-MULTI and parametric IO-429-EH Tx channels. This is a floating point attribute. To modify this attribute value, the KMXF_A429_ELECTRICAL_SELECTION attribute must be set to custom.

The supported range is:

Device	Range (V)
FlexMobile	-6.50 – +6.50
IPM-MULTI	-9.16 – +9.16
MXF_MODULE_MULTI_EH	see table below

Default value: -5.0 V

MXF_MODULE_MULTI_EH

Device Type	Revision	MXF Version	Range (Volt)
FlexMulti 629	Up to 2.4	Up to 4.2.5	-5.0 – +5.0
		4.3.0 to 4.4.1	-6.0 – +6.0
		4.4.2 and later	-6.1 – +6.1
	2.5 and later	Up to 4.2.5	-5.0 – +5.0
	2.5 and later	4.3.0 and later	-6.5 – +6.5
FlexMulti 1553	Up to 3.2	Up to 4.2.5	-5.0 – +5.0
		4.3.0 to 4.4.1	-6.0 – +6.0
		4.4.2 and later	-6.1 – +6.1
	3.3 and later	Up to 4.2.5	-5.0 – +5.0
	3.3 and later	4.3.0 and later	-6.5 – +6.5
FlexMulti 429 FlexMulti 664 FlexMulti	Up to 3.0	Up to 4.2.5	-5.0 – +5.0
		4.3.0 to 4.4.1	-6.0 – +6.0
		4.4.2 and later	-6.1 – +6.1
	3.1 and later	Up to 4.2.5	-5.0 – +5.0
	3.1 and later	4.3.0 and later	-6.5 – +6.5

TX Voltage Offset

The KMXF_A429_TX_VOLTAGE_OFFSET attribute defines the TX voltage offset for IO-MULTI-EH, IPM-MULTI and parametric IO-429-EH Tx channels. This is a floating point attribute. To modify this attribute value, the KMXF_A429_ELECTRICAL_SELECTION attribute must be set to custom.

The supported range is:

Device	Range (V)
FlexMobile	-6.50 – +6.50
IPM-MULTI	-10.0 – +10.0
MXF_MODULE_MULTI_EH	see table below

Default value: 0.0 V

MXF_MODULE_MULTI_EH

Device Type	Revision	MXF Version	Range (Volt)
FlexMulti 629	Up to 2.4	Up to 4.2.5	-5.0 – +5.0
		4.3.0 to 4.4.1	-6.0 – +6.0
		4.4.2 and later	-6.1 – +6.1
	2.5 and later	Up to 4.2.5	-5.0 – +5.0
	2.5 and later	4.3.0 and later	-6.5 – +6.5
FlexMulti 1553	Up to 3.2	Up to 4.2.5	-5.0 – +5.0
		4.3.0 to 4.4.1	-6.0 – +6.0
		4.4.2 and later	-6.1 – +6.1
	3.3 and later	Up to 4.2.5	-5.0 – +5.0
	3.3 and later	4.3.0 and later	-6.5 – +6.5
FlexMulti 429 FlexMulti 664 FlexMulti	Up to 3.0	Up to 4.2.5	-5.0 – +5.0
		4.3.0 to 4.4.1	-6.0 – +6.0
		4.4.2 and later	-6.1 – +6.1
	3.1 and later	Up to 4.2.5	-5.0 – +5.0
	3.1 and later	4.3.0 and later	-6.5 – +6.5

TX Differential Voltage

The KMXF_A429_TX_DIFF_VOLTAGE attribute defines the TX differential output voltage value for parametric IO-FLEX429 Tx channels. This is a floating point attribute.

The supported range is:

Model	Range (V)
FMX-A429-4TV4R	1.0 – 16.0

Default value: 10.0 V

RX Differential Voltage Threshold

The KMXF_A429_RX_DIFF_VOLTAGE_THRESHOLD attribute defines the RX differential voltage threshold for IO-MULTI-EH and IPM-MULTI Rx channels. This is a floating point attribute. To modify this attribute value, the KMXF_A429_ELECTRICAL_SELECTION attribute must be set to custom.

Range	Value (V)
Minimum	0.0
Maximum	25.0

Resolution: 0.05 V Default value: 4.49 V