The following attributes are available for all devices supporting a HDLC interface

Clock Source

The KMXF_HDLC_CLOCK_SOURCE attribute holds the actual clock source for each RX and TX channels. Usually, the RX channel clock source is external and the TX channel clock source is internal. When the internal loopback is enabled, this attribute becomes read-only. This attribute is not available when KMXF_HDLC_DATA_ENCODING is set to VMXF_HDLC_ENCODING_MANCHESTER_NOCLK.

The supported values are:

Constant	Value
VMXF_HDLC_CLOCK_SOURCE_EXTERNAL	The clock source is external (from the channel point of view, the clock source is an input). (default for RX channel)
VMXF_HDLC_CLOCK_SOURCE_INTERNAL	The clock source is internal (from the channel point of view, the clock source is an output). (default for TX channel)

Internal Clock Frequency

The KMXF_HDLC_INTERNAL_CLOCK_FREQ attribute holds the internal clock frequency for each RX and TX channels, in Hz. Used by all encodings except VMXF_HDLC_ENCODING_MANCHESTER_NOCLK.

The supported range is:

Module	Range (bps)	Default (bps)	Note
MXF_MODULE_MULTI_EH	490 - 4000000	1000000	Frequency = 10⁸ / n with 25 ≤ n ≤ 204080
MXF_MODULE_MULTI	490 - 4000000	1000000	Frequency = 4000000 / n with 1 ≤ n ≤ 16328
MXF_MODULE_FLEXSMP	200 - 4000000	1000000	Frequency = 100000000 / n with 25 ≤ n ≤ 500000

Speed

The KMXF_HDLC_SPEED attribute holds the speed for each RX and TX channels, in Bps. Used only with VMXF_HDLC_ENCODING_MANCHESTER_NOCLK encoding.

The supported range is:

Module	Range (bps)	Default (bps)	Note
MXF_MODULE_MULTI	490 - 4000000	1000000	Frequency = 4000000 / n with 1 ≤ n ≤ 16328
MXF_MODULE_FLEXSMP	200 - 4000000	1000000	Frequency = 100000000 / n with 25 ≤ n ≤ 500000

TX Interframe Time Fill

The KMXF_HDLC_TX_INTERFRAME_TIME_FILL attribute holds the inter-frame time fill option.

The supported values are:

Constant	Value
VMXF_HDLC_TX_INTERFRAME_TIME_FILL_NONE	No flags will be sent between transmission (idle time). Allows other stations on the bus to transmit.
VMXF_HDLC_TX_INTERFRAME_TIME_FILL_FLAGS	Flags will be sent between transmission. No other stations on the bus are allowed to transmit. (default)

Note: The first transmission will automatically enable the transmitter. The transmitter remains enabled after the transmission is completed. To disable the transmitter, set the KMXF_HDLC_TX_INTERFRAME_TIME_FILL attribute to VMXF_HDLC_TX_INTERFRAME_TIME_FILL_NONE. MAXT_ERROR_TRANSMITTER_ENABLED error will be returned when trying to modify some transmission properties even if there is no transmission queued. The transmitter needs to be disabled with VMXF_HDLC_TX_INTERFRAME_TIME_FILL_NONE (even if it's already set to VMXF_HDLC_TX_INTERFRAME_TIME_FILL_NONE).

Data Encoding

The KMXF_HDLC_DATA_ENCODING attribute defines the transmission/reception data encoding.

Clock frequency for all encoding except VMXF_HDLC_ENCODING_MANCHESTER_NOCLK is set with KMXF_HDLC_INTERNAL_CLOCK_FREQ. Speed of VMXF_HDLC_ENCODING_MANCHESTER_NOCLK is set with KMXF_HDLC_SPEED.

The supported values are:

Constant	Value
VMXF_HDLC_ENCODING_NRZ	NRZ encoding used (default)
VMXF_HDLC_ENCODING_NRZI	NRZI (NRZ-S) encoding used
VMXF_HDLC_ENCODING_FM1	FM1 encoding used
VMXF_HDLC_ENCODING_FM0	FM0 encoding used
VMXF_HDLC_ENCODING_MANCHESTER	Manchester encoding used
VMXF_HDLC_ENCODING_MANCHESTER_NOCLK	Manchester no clock encoding used (IPM-MULTI rev B2 and later, FlexMulti 629/1553 with package revision 1.1.16 and later with MXF 4.6.6 and later, FlexMulti 429/664 with package revision 1.1.18 and later with MXF 4.6.6 and later and IO-FLEXSMP module)

Frame Size Enable

The KMXF_HDLC_FRAME_SIZE_ENABLE attribute holds the Frame Size word enabled state.

The supported values are:

Constant

Value

VMXF_ENABLE

A Frame Size value will be placed at the end of the frame (last word of the frame if FCS is not enabled, the word before FCS if enabled). The frame size value is 16-bit and it represents the total number of bytes in the frame. The frame must be at least two bytes long if FCS is not enabled or 4 bytes long if FCS is enabled. In transmission, if the message spans over more than one data record, use MXF_HDLC_TX_REC_CTRL_FRAMESIZE_NOT_SEND control bit in data record that must not have the frame size field.

VMXF_DISABLE

No Frame Size value will be sent.

FCS Type

The KMXF_HDLC_FCS_TYPE attribute holds the Frame Check Sequence type.
In transmission, if the message spans over more than one data record, use MXF_HDLC_TX_REC_CTRL_FCS_NOT_SEND control bit in data record that must not have the FCS field.

The supported values are:

Constant	Value
VMXF_HDLC_TX_RX_FCS_NONE	In transmission, no FCS value will be sent. In Reception, no FCS value will be checked.
VMXF_HDLC_TX_RX_FCS_CCITT (default)	In transmission, FCS value using CRC-16-CCITT will be sent at the location of the last word of the frame. In Reception, FCS value (last word of the frame) using CRC-16-CCITT will be checked and MXF_HDLC_RX_REC_CTRL_FCS_ERROR bit set in MXF_HDLC_DATAREC.control field if does not match. This FCS is also known as CRC-CCITT, CRC-16/X-25, CRC-16/IBM-SDLC or CRC-16/ISO-HDLC.
VMXF_HDLC_TX_RX_FCS_16	In transmission, FCS value using CRC-16-IBM will be sent at the location of the last word of the frame. In Reception, FCS value (last word of the frame) using CRC-16-IBM will be checked and MXF_HDLC_RX_REC_CTRL_FCS_ERROR bit set in MXF_HDLC_DATAREC.control field if does not match. This FCS is also known as CRC-16 or CRC-16/USB.

Note

VMXF_HDLC_TX_RX_FCS_CCITT implementation:

Parameters	Value
Polynomial	0x1021 (x16 + x12 + x5 + 1)
Initial value	0xffff
Output XOR	0xffff
Input	reflected
Output	reflected

VMXF_HDLC_TX_RX_FCS_16 implementation:

Parameters	Value
Polynomial	0x8005 (x16 + x15 + x2 + 1)
Initial value	0xffff
Output XOR	0xffff
Input	reflected
Output	reflected

Loopback Mode

The KMXF_HDLC_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 internal transmitter instead of the default configuration where the received data come from the RX line circuit. This feature is intended for a demo application or for testing purposes. When enabled, the module's first RX channel receives data transmitted on the first TX channel; the second RX channel receives data from the second TX channel, and so on. When internal loopback is enabled, the KMXF_HDLC_CLOCK_SOURCE attribute becomes read-only.

The supported values are:

Constant	Value
VMXF_ENABLE	Enable loopback
VMXF_DISABLE	Disable loopback (default)

Edge Selection

The KMXF_HDLC_EDGE_DETECTION attribute defines the edge selection for the channel.

This attribute is not available when KMXF_HDLC_DATA_ENCODING is set to VMXF_HDLC_ENCODING_MANCHESTER_NOCLK.

Note: Attribute available on IPM-MULTI rev B1 and later, FlexMulti 629/1553 with package revision 1.1.16 and later with MXF 4.6.6 and later, FlexMulti 429/664 with package revision 1.1.18 and later with MXF 4.6.6 and later and IO-FLEXSMP module.

The supported values are:

Constant	Value
VMXF_HDLC_EDGE_DETECTION_FALLING	Falling edge (default Rx)
VMXF_HDLC_EDGE_DETECTION_RISING	Rising edge (default Tx)

Electrical Interface

The KMXF_HDLC_ELECTRICAL_INTERFACE attribute defines the electrical interface for the Tx channel.

Note: Attribute available on IPM-MULTI rev B1 and later with MXF 4.4.2 and later, FlexMulti 629/1553 with package revision 1.1.16 and later with MXF 4.6.6 and later, FlexMulti 429/664 with package revision 1.1.18 and later with MXF 4.6.6 and later and IO-FLEXSMP module.

The supported values are:

Constant	Value
VMXF_HDLC_ELECTRICAL_INTERFACE_RS422	RS-422
VMXF_HDLC_ELECTRICAL_INTERFACE_RS485	RS-485 (default)

Termination Resistor

The KMXF_HDLC_TERMINATION attribute holds the actual channel termination resistor state.
Only supported on MXF_MODULE_FLEXSMP.

Constant	Value
VMXF_HDLC_TERMINATION_NONE	No termination resistor (default)
VMXF_HDLC_TERMINATION_120OHM	120 ohm termination resistor enabled

Electrical Selection

The KMXF_HDLC_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 the KMXF_HDLC_ELECTRICAL_SELECTION attribute to VMXF_HDLC_TX_SLEW_RATE_SELECT_CUSTOM.
Not supported on MXF_MODULE_FLEXSMP.

Electrical attributes:

The supported values are:

Constant	Value
VMXF_HDLC_ELECTRICAL_SELECT_DEFAULT	Select default electrical parameters (default)
VMXF_HDLC_ELECTRICAL_SELECT_CUSTOM	Select custom electrical parameters

RX Differential Voltage Threshold

The KMXF_HDLC_RX_DIFF_VOLTAGE_THRESHOLD attribute defines the RX differential voltage threshold. This is a floating point attribute. To modify this attribute value, the KMXF_HDLC_ELECTRICAL_SELECTION attribute must be set to VMXF_HDLC_ELECTRICAL_SELECT_CUSTOM.
Not supported on MXF_MODULE_FLEXSMP.

The supported range is:

Constant	Value (Volt)
Minimum	0.0
Maximum	25.0

Resolution: ≈0.05 volt Default value: 0.21.

TX Slew Rate Selection

The KMXF_HDLC_TX_SLEW_RATE_SELECTION attribute defines the TX slew rate selection. MX Foundation automatically calculates the default slew rate based on the channel speed, high and low differential voltage and voltage offset value. When the default option (VMXF_HDLC_TX_SLEW_RATE_SELECT_DEFAULT) is selected, the KMXF_HDLC_TX_SLEW_RATE attribute will be read only. Otherwise, the custom option (VMXF_HDLC_TX_SLEW_RATE_SELECT_CUSTOM) allows specifying the slew rate using the KMXF_HDLC_TX_SLEW_RATE attribute.
Not supported on MXF_MODULE_FLEXSMP.

The supported values are:

Constant	Value
VMXF_HDLC_TX_SLEW_RATE_SELECT_DEFAULT	Select default slew rate parameters (default)
VMXF_HDLC_TX_SLEW_RATE_SELECT_CUSTOM	Select custom slew rate parameters

TX Slew Rate

The KMXF_HDLC_TX_SLEW_RATE attribute defines the TX slew rate value. The KMXF_HDLC_ELECTRICAL_SELECTION attribute must be set to VMXF_HDLC_TX_SLEW_RATE_SELECT_CUSTOM in order to specify the slew rate using this attribute. This is a floating point attribute. Value will be rounded to closest supported step.

The supported range is:

Module	Range (nsec/volt)	Default (nsec/volt)	Formula
MXF_MODULE_MULTI_EH	2.0 - 13429.5	2.0	(204800/1.22) / (n*3.125) with 4 ≤ n ≤ 26856
MXF_MODULE_MULTI	25.0 - 25600.0	25.0	102400/n with 4096 ≤ n ≤ 51200

TX Differential Voltage High

The KMXF_HDLC_TX_DIFF_VOLTAGE_HIGH attribute defines the high TX differential voltage value. To modify this attribute value, the KMXF_HDLC_ELECTRICAL_SELECTION attribute must be set to VMXF_HDLC_TX_SLEW_RATE_SELECT_CUSTOM. This is a floating point attribute.

The supported range is:

Module	Range (Volt)	Default (Volt)
MXF_MODULE_MULTI_EH	see table below	2.5
MXF_MODULE_MULTI	-9.16 – +9.16	1.9

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
		4.3.0 to 4.4.1	-6.0 – +6.0
		4.4.2 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
		4.3.0 to 4.4.1	-6.0 – +6.0
		4.4.2 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
		4.3.0 to 4.4.1	-6.0 – +6.0
		4.4.2 and later	-6.5 – +6.5

TX Differential Voltage Low

The KMXF_HDLC_TX_DIFF_VOLTAGE_LOW attribute defines the low TX differential voltage value. To modify this attribute value, the KMXF_HDLC_ELECTRICAL_SELECTION attribute must be set to VMXF_HDLC_TX_SLEW_RATE_SELECT_CUSTOM. This is a floating point attribute.

The supported range is:

Module	Range (Volt)	Default (Volt)
MXF_MODULE_MULTI_EH	see table below	-2.5
MXF_MODULE_MULTI	-9.16 – +9.16	-1.9

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
		4.3.0 to 4.4.1	-6.0 – +6.0
		4.4.2 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
		4.3.0 to 4.4.1	-6.0 – +6.0
		4.4.2 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
		4.3.0 to 4.4.1	-6.0 – +6.0
		4.4.2 and later	-6.5 – +6.5

TX Voltage Offset

The KMXF_HDLC_TX_VOLTAGE_OFFSET attribute defines the TX voltage offset. To modify this attribute value, the KMXF_HDLC_ELECTRICAL_SELECTION attribute must be set to VMXF_HDLC_TX_SLEW_RATE_SELECT_CUSTOM. This is a floating point attribute.
Not supported on MXF_MODULE_FLEXSMP.

The supported range is:

Module	Range (Volt)	Default (Volt)
MXF_MODULE_MULTI_EH	see table below	2.5
MXF_MODULE_MULTI	-10.0 – +10.0	1.9

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
		4.3.0 to 4.4.1	-6.0 – +6.0
		4.4.2 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
		4.3.0 to 4.4.1	-6.0 – +6.0
		4.4.2 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
		4.3.0 to 4.4.1	-6.0 – +6.0
		4.4.2 and later	-6.5 – +6.5

RX FIFO Aging Timeout

The KMXF_HDLC_MODULE_RX_FIFO_AGING attribute defines the FIFO aging timeout value for a receiver channel. 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 128 microseconds.

The supported range is:

Module	Range (microsecond)	Default (microsecond)	Note
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_FLEXSMP	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 this attribute unless told to do so by a MAX Technologies' support engineer.

RX FIFO Almost Full Threshold

The KMXF_HDLC_MODULE_RX_FIFO_AF attribute holds the almost full threshold for a receiver channel. This attribute value determines the number of received words that must be accumulated in the receive hardware FIFO before an interrupt is generated.

The supported range is:

Module	Range	Default
MXF_MODULE_MULTI_EH	1 - 255 (16-bit word)	32
MXF_MODULE_MULTI	1 - 255 (16-bit word)	16
MXF_MODULE_FLEXSMP	1 - 511 (64-bit word)	128

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

TX FIFO Almost Full Threshold

The KMXF_HDLC_MODULE_TX_FIFO_AF attribute holds the almost full threshold for a transmitter channel. The attribute value determines the maximum number of transmit words that are queued in the transmit hardware FIFO. The transmit interrupt will be cleared automatically once this threshold is reached.

The supported range is:

Module	Range	Default
MXF_MODULE_MULTI_EH	2 - 255 (16-bit word)	128
MXF_MODULE_MULTI	2 - 255 (16-bit word)	128
MXF_MODULE_FLEXSMP	2 - 256 (64-bit word)	256

Note: MX Foundation takes care of initializing this attribute using the optimal value. It is not recommended to change this attribute unless told to do so by a MAX Technologies' support engineer.; At high speed (>= 1Mbps), the receiver can detect gaps between words, that will be seen as an abort. In this case, the KMXF_HDLC_MODULE_TX_FIFO_AF and KMXF_HDLC_MODULE_TX_FIFO_AE values must be set to a greater value.

TX FIFO Almost Empty Threshold

The KMXF_HDLC_MODULE_TX_FIFO_AE attribute holds the almost empty threshold for a transmitter channel. The attribute value determines when the transmit interrupt will be generated. The transmit interrupt will be generated whenever the number of word remaining in the transmit hardware FIFO is less than or equal to the value specified through this attribute. The software embedded process, will then be able to react and fill in the transmit FIFO.

The supported range is:

Module	Range	Default
MXF_MODULE_MULTI_EH	1 - 254 (16-bit word)	64
MXF_MODULE_MULTI	1 - 254 (16-bit word)	64
MXF_MODULE_FLEXSMP	1 - 255 (64-bit word)	64

Note: MX Foundation takes care of initializing this attribute using the optimal value. It is not recommended to change this attribute unless told to do so by a MAX Technologies' support engineer.; At high speed (>= 1Mbps), the receiver can detect gaps between words, that will be seen as an abort. In this case, the KMXF_HDLC_MODULE_TX_FIFO_AF and KMXF_HDLC_MODULE_TX_FIFO_AE values must be set to a greater value.

RX Time tag Enable

The KMXF_HDLC_MODULE_RX_TIMETAG_ENABLE attribute defines the RX time tag enable state. When the time tag reception is disabled, the timeTag field of MXF_HDLC_DATAREC will always be 0. 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 supported on MXF_MODULE_FLEXSMP.

The supported values are:

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