IP Integration | Holoscan Sensor Bridge Documentation

Top Level Module

The top level module of the Holoscan Sensor Bridge IP is “HOLOLINK_top”.

User Configurability

The Holoscan Sensor Bridge (HSB) IP is designed to be easily configurable to various use case of the IP, such as number of sensors and Ethernet ports. It’s also designed to be compatible with multiple FPGA vendors. The following describes the configurations available to user.

Macro Definitions

The Holoscan Sensor Bridge definitions file, “HOLOLINK_def.svh”, defines the following macros.

The macros can be configured to user’s application of the Holoscan Sensor Bridge IP. The default macro value is the configuration that has been tested and verified.

Table 1

Macro	Tested Values	Description
HIF_CLK_FREQ	156250000 (for DATAPATH_WIDTH=64) 201416016 (for DATAPATH_WIDTH=512)	Clock frequency of the Host Interface. Unit is in Hz
APB_CLK_FREQ	19531250 (for DATAPATH_WIDTH=64) 100000000 (for DATAPATH_WIDTH=512)	Clock frequency of the APB Interface. Unit is in Hz
PTP_CLK_FREQ	100446545	Clock frequency of the PTP Interface. Unit is in Hz. Range 95MHz to 105MHz
UUID[127:0]	128’h889B7CE3_65A5_4247_8B05_4FF1904C3359 for Lattice LF-SNSR-ETH-EVN 128’hED6A9292_DEBF_40AC_B603_A24E025309C1 for Microchip MPF200-ETH-SENSOR-BRIDGE 128’hF1627640_B4DC_48AF_A360_C65B09B3D230 for Leopard Imaging VB1940 Eagle Camera 128’h9957A9AC_36B5_4518_83EC_5D514AECB750 for TauroTech DA326	Universally Unique Identifier are used to identify the board to fetch and remote flash the correct bitfile.
ENUM_EEPROM	Defined or undefined	When defined, read the contents of the Enumeration packet from external non-volatile memory. If undefined, use the macros defined below..
EEPROM_REG_ADDR_BITS	8 or 16	Valid when ENUM_EEPROM is defined. Number for register address bits used in the EEPROM.
DATAPATH_WIDTH	8, 16, 32, 64, 128, 256, 512, 1024	Width of the Sensor AXI Stream TDATA in bits. This number must be byte-aligned. Meaning, it must be a number divisible by 8.
DATAKEEP_WIDTH	DATAPATH_WIDTH/8	Width of the Sensor AXI Stream TKEEP.This should not be changed.
DATAUSER_WIDTH	1-2	Width of the Sensor AXI Stream TUSER signal.
SENSOR_RX_IF_INST	undefined, 1-32	Number of Sensor RX Interface.
SIF_RX_WIDTH[SENSOR_RX_IF_INST-1:0]	8, 16, 32, 64, 128, 256, 512, 1024	Valid when SENSOR_RX_IF_INST is defined. Each Sensor RX interface width can be individually defined. Max value should be DATAPATH_WIDTH.
SIF_RX_DATA_GEN	undefined, defined	Valid when SENSOR_RX_IF_INST is defined. Instantiates a Data Generator module to test Sensor to Host data path.
SIF_RX_PACKETIZER_EN[SENSOR_RX_IF_INST-1:0]	0, 1	Valid when SENSOR_RX_IF_INST is defined. Each Sensor RX interface Packetizer can be individually enabled.
SIF_RX_VP_COUNT[SENSOR_RX_IF_INST-1:0]	DO NOT TOUCH	Valid when SENSOR_RX_IF_INST and SIF_RX_PACKETIZER_EN is defined. TBD. Do not change.
SIF_RX_SORT_RESOLUTION[SENSOR_RX_IF_INST-1:0]	DO NOT TOUCH	Valid when SENSOR_RX_IF_INST and SIF_RX_PACKETIZER_EN is defined. TBD. Do not change.
SIF_RX_VP_SIZE[SENSOR_RX_IF_INST-1:0]	DO NOT TOUCH	Valid when SENSOR_RX_IF_INST and SIF_RX_PACKETIZER_EN is defined. TBD. Do not change.
SIF_RX_NUM_CYCLES[SENSOR_RX_IF_INST-1:0]	DO NOT TOUCH	Valid when SENSOR_RX_IF_INST and SIF_RX_PACKETIZER_EN is defined. TBD. Do not change.
SENSOR_TX_IF_INST	undefined, 1-32	Number of Sensor TX Interface.
SIF_TX_WIDTH[SENSOR_TX_IF_INST-1:0]	8, 64, 512	Valid when SENSOR_TX_IF_INST is defined. Each Sensor TX interface width can be individually defined. Max value should be DATAPATH_WIDTH.
SIF_TX_BUF_SIZE[SENSOR_TX_IF_INST-1:0]	1024, 2048, 4096	Valid when SENSOR_TX_IF_INST is defined. Set the Sensor TX Buffer Size.
HOST_WIDTH	8, 16, 32, 64, 128, 256, 512	Width of the Host AXI Stream TDATA in bits. This number must be byte-aligned. Meaning, it must be a number divisible by 8.
HOSTKEEP_WIDTH	HOST_WIDTH/8	Width of the Host AXI Stream TKEEP.This should not be changed.
HOSTUSER_WIDTH	1	Width of the Host AXI Stream TUSER signal.
HOST_IF_INST	1-32	Number of Host interfaces.
HOST_MTU	1500, 4096	Size of Ethernet packet in bytes.
SPI_INST	undefined, 1-8	Number of SPI interfaces.
I2C_INST	undefined, 1-8	Number of I2C interfaces.
UART_INST	undefined, 1	Number of UART interfaces.
GPIO_INST	1-255	Number of GPIO Input & Output bits.
GPIO_RESET_VALUE[GPIO_INST-1:0]	0	Reset value of GPIO bits.
REG_INST	1-8	Number of user register.
N_INIT_REG	undefined, Integer value	Number of initialization registers.

Build Revision

Parameter BUILD_REV[47:0] can be passed down to the “HOLOLINK_top” module to uniquely identify the FPGA build revision.

Sensor Interface Configuration

In applications where the HSB IP connects multiple sensors with varying bandwidths, the IP can be configured on a per-sensor-interface basis to optimize resource utilization.

The DATAPATH_WIDTH parameter defines the AXI Stream vector width for all sensor interfaces to simplify integration and should be set to match the widest sensor. The SIF_RX_WIDTH and SIF_TX_WIDTH parameters can be configured individually to specify narrower data widths for each sensor interface.

For example, if the first sensor interface has a width of 64 bits and the second has 32 bits: Set DATAPATH_WIDTH to 64 and set SIF_RX_WIDTH to {32, 64}. For second sensor interface, only the [31:0] of the AXI Stream TDATA and [3:0] of the AXI Stream TKEEP are used and the remaining signals should be tied to 0. The LSB [3:0] of AXI Stream TKEEP is still required to be set to all 1’b1.

Furthermore, the Packetizer function, which is needed when streaming camera to Thor, can be enabled for each sensor interface. For example, if the first sensor needs the Packetizer function but the second sensor does not, set SIF_RX_PACKETIZER_EN parameter to {0,1}.

HSB IP supports Virtual Port mapping. For more information, refer to Sensor Interface to Virtual Port Mapping

BOOTP Packet

The HSB IP transmits a broadcast BOOTP Request packet (adhering to RFC-951) on each Host interface. BOOTP Request packets are used to enumerate the HSB to host and to change the IP address from default in case of multiple board enumeration. Default IP address of HSB IP is “192.168.0.2” for Host interface 0 and “192.168.0.3” for Host interface 1 and so on. BOOTP Request packets are sent once a second. If PTP internal to the HSB IP is used, BOOTP packet is sent every pulse-per-second (PPS) which is internally generated in the “i_ptp_clk” domain. If EXT_PTP macro is defined, then PPS is internally generated when the LSB of “i_ptp_sec” input port toggles.

The Vendor Field of the BOOTP packet is used to communicate enumeration info and status of HSB to the host. The BOOTP Vendor field is laid out in below table:

Table 2

Byte Number	Description	Value
[0]	Vendor Tag	0xE0
[1]	Tag Length	0x38
[5:2]	ASCII “NVDA”	0x4144564E, in Big Endian format
[6]	Ethernet Port Number	0x0 for Port 0 , 0x1 for Port 1
[7]	Enumeration Version	0x2
[9:8]	Reserved	Reserved. Set to 0.
[25:10]	UUID	UUID defined in HOLOLINK_def.svh. Big Endian format
[29:26]	Reserved	Reserved.
[36:30]	Board Serial Number	BOARD_SN fetched from EEPROM or from HSB IP input port. Little Endian format.
[38:37]	Holoscan Sensor Bridge IP Version	0x2606 for Holoscan SDK v2.7.0 release. Little Endian format.
[44:39]	Reserved	Reserved.
[54:45]	PTP Timestamp	PTP Timestamp. Seconds and Nanoseconds in PTP v2 format. Big Endian format.
[56:55]	Packet Sequence Number	Packet Sequence Number. Increments per BOOTP packet sent. Big Endian format.
[57]	Status	0x1 when PTP is enabled in HSB and a SYNC PTP packet has been received.
[63:58]	Reserved	Reserved. Set to 0.

Each of the macros used for enumeration packet is further explained below.

UUID: This macro defines the unique identifier for the board. Holoscan uses this value to identify which board it is interfacing and fetch the correct bitfile for remote flash. For newly developed boards, users can generate and assign a new UUID. This macro must be defined and is not optionally stored in the non-volatile memory.

ENUM_EEPROM: When this macro is defined, enumeration fields, the MAC address and Board Serial Number, are retrieved from an on-board, non-volatile memory upon boot-up. The enumeration fields are retrieved over I2C port 0 with EEPROM 7-bit address 0x50.

Mass production of boards with Holoscan Sensor Bridge IP requires an external EEPROM to store unique MAC address and board serial numbers. When using evaluation platforms for test and bring-up, enumeration fields, MAC address and Board Serial Number, can be passed to HSB IP via input port.

When retrieving from EEPROM, the MAC address and board serial number must be placed in these EEPROM register address.

EEPROM address (decimal)	MAC bits
68	MAC[47:40]
69	MAC[39:32]
70	MAC[31:24]
71	MAC[23:16]
72	MAC[15:8]
73	MAC[7:0]
74	Board SN[55:48]
75	Board SN[47:40]
76	Board SN[39:32]
77	Board SN[31:24]
78	Board SN[23:16]
79	Board SN[15:8]
80	Board SN[7:0]

System Initialization

The Holoscan Sensor Bridge IP provides system initialization function to write to registers upon power up. This function is used to initialize the Ethernet block to establish ethernet connection between the FPGA and the host, and can be used for any other user function in the top level design.

The list of registers to be initialized is defined in “HOLOLINK_def.svh” as “init_reg” array. The “init_reg” is an unpacked array, sized [N_INIT_REG] [63:0], where the N_INIT_REG macro defines the number of registers to be initialized and the 64-bit vector is used to define the 32-bit address of register at [63:32] and the 32-bit write data at [31:0].

To give an example of one of the init_reg array entry:

{32'h1000_0020, 32'h0000_00FF} //init_reg[0]

Will write to the User REG_INST_0 block address offset 0x0000_0020 the data 0x0000_00FF.

Once system initialization is complete, the “o_init_done” port will be asserted high in “i_apb_clk” domain. User can use this signal to gate their logic if it’s dependent on ethernet block initialization.