HDL Architecture#

Every HDL design of a reference project can be divided into two subsystems:

Base design — description of what the carrier contains:
- an embedded processor - soft or hard
- all the peripheral IPs (that are necessary to run a Linux distribution on the system)
- these designs are specific to each carrier, making them carrier dependent
- it describes part of the system_wrapper module
- located in projects/common; one for each carrier
Board design — description of what the board attached to the carrier contains:
- all the necessary IPs needed to support the board
- these designs are common to all carriers, making them carrier independent
- it describes part of the system_wrapper module
- located in hdl/projects/$project_name/common/*bd.tcl

How they’re instantiated#

In case of a project, inside the system_bd.tcl file, we have to source the base design first, then the board design.

Example#

Take AD-FMCOMMS2-EBZ with ZedBoard; the system_bd.tcl will look like the following:

source $ad_hdl_dir/projects/common/zed/zed_system_bd.tcl
source ../common/fmcomms2_bd.tcl

Typical project diagram#

HDL overall system

Base Design#

The base design contains all the I/O peripherals, memory interfaces and processing components, which are necessary for a fully functional Linux system. The majority of these components are Intel and AMD Xilinx IP cores.

Usually, they contain:

Microprocessor
Memory interface controller
Peripheral interfaces

Microprocessor#

In our designs, we use only two types:

Intel		AMD Xilinx
SoC	FPGA	SoC	FPGA	ACAP
HPS	NIOS II	PS7 PS8	MicroBlaze	Versal

Worth mentioning in case of SoCs, the Hard Processor System (HPS) or Processing System 7/8 (PS7/8) do not contain just the dual-core ARM® Cortex® - A9 MPCore™ processor, they also have other integrated peripherals and memory interfaces. For more information please visit the manufacturer’s website, listed in the table above.

PS7 — Zynq-7000 SoC Processing System (processing_system7)
PS8 — Zynq UltraScale+ MPSoC Processing System (zynq_ultra_ps_e)
Versal — Versal ACAP CIPS (versal_cips)

Memory Interface Controller#

In almost all cases, the carrier board is not made and designed by Analog Devices, so the external memory solution of the system is given. Meaning we can not support, modify or alter this important part of the system, in several cases we even have system limitations because of it (e.g. the memory interface is not fast enough to handle the required data throughput).

Under the two links below the user can find the landing page of the available memory solutions for both Intel and AMD:

Intel’s memory interfaces: https://www.intel.com/content/www/us/en/programmable/support/support-resources/external-memory.html
AMD’s memory interfaces: https://www.xilinx.com/products/intellectual-property/mig.html#documentation

Peripheral interfaces#

These interfaces are used to control external peripherals located on the prototyping board or the FMC IO board.

In HDL, these ports are named slightly different than how they’re in the documentations. Thus, to make it easier for beginners, here you have the naming of the ports depending on the microprocessor used.

CPU/Memory interconnects addresses#

The memory addresses that will be used by software are based on the HDL addresses of the IP register map, to which an offset is added, depending on the architecture of the used FPGA (see also ad_cpu_interconnect procedure; architecture is specified by sys_zynq variable, for AMD FPGAs).

Zynq-7000 and 7 Series

Because this was the original target, this is the reference address used, the common one, to which depending on the architecture, you add an offset to get to the address space for the peripherals (as they differ from one to the other).

Zynq UltraScale+ MP

If the address is between 0x4000_0000 - 0x4FFF_FFFF then the AXI peripherics will be placed in 0x8000_0000 - 0x8FFF_FFFF range by adding 0x4000_0000 to the address.

If the address is between 0x7000_0000 - 0x7FFF_FFFF then the AXI peripherics will be placed in 0x9000_0000 - 0x9FFF_FFFF range by adding 0x2000_0000 to the address.

Versal

If the address is between 0x4400_0000 - 0x4FFF_FFFF then the AXI peripherics will be placed in 0xA400_0000 - 0xAFFF_FFFF range by adding 0x6000_0000 to the address.

If the address is between 0x7000_0000 - 0x7FFF_FFFF then the AXI peripherics will be placed in 0xB000_0000 - 0xBFFF_FFFF range by adding 0x4000_0000 to the address.

SPI#

In general, the base system has two Serial Peripheral Interfaces, which are used as a control interface for FMC/HSMC devices. These SPI interfaces are controlled by the integrated SPI controller of the Hard Processor System (HPS) or Processing System 7/8 (PS7/8) or an Intel or AMD SPI controller core.

I2C/I2S/SPDIF#

A couple of carrier boards require these standard interfaces for different purposes, for example, a configuration interface for an audio peripheral device. These peripherals do not necessarily have vital roles in the reference design, it’s more like a generic goal to support all the provided peripherals of the carrier board.

HDMI#

There is HDMI support for all the carriers which are using the ADV7511 as HDMI transmitter. The HDMI transmitter core can be found here.

GPIOs#

The general rule of thumb is to define 64 GPIO pins for the base design:

bits [31: 0] always belong to the carrier board;
bits [63:32] will be assigned to switches, buttons and/or LEDs, which can be found on the FMC board.
bits [95:64] will be used when the FPGA type is Zynq UltraScale+ MPSoC

When some of these GPIOs are not used, the input pins should have the output pins driven to them, so that Vivado will not complain about inputs not being assigned to.

Depending on the processor type, add these values to the GPIO number from the HDL project to obtain the final number used in software:

PS7 EMIO offset = 54
PS8 EMIO offset = 78

Connectivity#

Ethernet
USB OTG

These interfaces designs are borrowed from the golden reference design of the board.

Interrupts#

When developing the Linux software parts for an HDL project, the interrupts number to the PS have a different number in the software side.

Not a rule, but in our designs we preffer to use firstly the interrupts from 15 and to go down to 0. Be careful when assigning one, because it might be used in the base design of the carrier!

Always check which are used (in /projects/common/$carrier/$carrier_system_bd.tcl)

Interrupts table#

HDL	Linux Zynq	Actual Zynq	Linux ZynqMP	Actual ZynqMP	S10SoC	Linux Cyclone V	Actual Cyclone V
15	59	91	111	143	32	55	87
14	58	90	110	142	31	54	86
13	57	89	109	141	30	53	85
12	56	88	108	140	29	52	84
11	55	87	107	139	28	51	83
10	54	86	106	138	27	50	82
9	53	85	105	137	26	49	81
8	52	84	104	136	25	48	80
7	36	68	96	128	24	47	79
6	35	67	95	127	23	46	78
5	34	66	94	126	22	45	77
4	33	65	93	125	21	44	76
3	32	64	92	124	20	43	75
2	31	63	91	123	19	42	74
1	30	62	90	122	18	41	73
0	29	61	89	121	17	40	72

Board design and capabilities#

AMD platforms#

Board name	Boots from	FMC connector 1	FMC connector 2	VADJ FMC connector	Family
AC701	JTAG	HPC (2 GTP @ 6.6 Gbps)	—	3.3V/*2.5V/1.8V	Artix-7
Cora Z7-07S	SD card	—	—	—	Zynq-7000
KC705	JTAG	HPC (4 GTX @ 10.3125 Gbps)	LPC (1 GTX @ 10.3125 Gbps)	3.3V/*2.5V/1.8V	Kintex-7
KCU105	JTAG	HPC (8 GTH @ 16.3 Gbps)	LPC (1 GTH @ 16.3 Gbps)	*1.8V/1.5V/1.2V	Kintex UltraScale
Microzed	JTAG	—	—	—	Zynq-7000
VC707	JTAG	HPC (8 GTX @ 12.5 Gbps)	HPC (8 GTX @ 12.5 Gbps)	*1.8V/1.5V/1.2V	Virtex-7
VC709	JTAG	HPC (10 GTH @ 13.1 Gbps)	—	*1.8V	Virtex-7
VCK190	SD card	FMC+ (12 GTY @ 28.21 Gbps)	FMC+ (12 GTY @ 28.21 Gbps)	*1.5V/1.2V	Versal AI Core
VCU118	JTAG	FMC+ (24 GTY @ 28.21 Gbps)	LPC	*1.8V/1.5V/1.2V	Virtex UltraScale+
VCU128	JTAG	FMC+ (24 GTY @ 28.21 Gbps)	—	*1.8V/1.5V/1.2V	Virtex UltraScale+ HBM
VMK180	SD card	FMC+ (12 GTY @ 28.21 Gbps)	FMC+ (12 GTY @ 28.21 Gbps)	*1.5V/1.2V	Versal Prime Series
VPK180	SD card	FMC+ (8 GTYP @ 32.75 Gbps)	—	*1.5V/1.2V	Versal Premium
ZC702	SD card	LPC	LPC	3.3V/*2.5V/1.8V	Zynq-7000
ZC706	SD card	HPC (8 GTX @ 10.3125 Gbps)	LPC (1 GTX @ 10.3125 Gbps)	3.3V/*2.5V/1.8V	Zynq-7000
ZCU102	SD card	HPC (8 GTH @ 16.3 Gbps)	HPC (8 GTH @ 16.3 Gbps)	*1.8V/1.5V/1.2V	Zynq UltraScale+ MP SoC
ZedBoard	SD card	LPC	—	3.3V/2.5V/*1.8V	Zynq-7000

Note

The column with the VADJ value applies to the FMC connectors when they exist. If both of them exist, then it is the same for both of them. If there is only one FMC connector, then it applies to only one. If both are missing, then a — (dash) will appear.

Note

(* bold) = default VADJ FMC1 & FMC2 columns -> depending on the power supply of the device connected to the FMC, the custom VADJ will have the value supported by both the carrier and the device(s)

Intel platforms#

Board name	FMC connector 1	FMC connector 2
A10GX	LPC ()	HPC (8 x 17.4 Gbps)
A10SoC	HPC (8)	LPC (8)
S10SoC	FMC+ (24 @ 28.3 Gbps)	FMC+ (24 @ 28.3 Gbps)

VADJ values#

Board name	FMC connector 1	FMC connector 2
A10GX	*1.8V/1.5V/1.35V/1.2V	*1.8V/1.5V/1.35V/1.2V
A10SoC	*1.8V/1.5V/1.35V/1.25V/1.2V/1.1V	*1.8V/1.5V/1.35V/1.2V/1.1V
S10SoC	*3.3V/1.8V/1.2V	*3.3V/1.8V/1.2V

(* bold) = default VADJ FMC1 & FMC2 columns -> depending on the power supply of the device connected to the FMC, the custom VADJ will have the value supported by both the carrier and the device(s)

File structure of a project#

Tip

In /projects/common/$carrier_name/ you can find templates for the system_top.v, Makefile, etc. to help you when creating a new project.

Project files for AMD boards#

A project for an AMD FPGA board should contain the following files:

Makefile — auto-generated file; contains all the IP dependencies needed for the project to be built
system_project.tcl — script that creates the actual Vivado project and runs the synthesis/implementation of the design
system_bd.tcl — sources the base design first, then the board design, and afterwards it contains all the IP instances and connections that must be added on top of the sourced files, to complete the design of the project (these are specific to the combination of this carrier and board)
system_constr.xdc — constraints file of the design; it’s the connection between the physical pins of the FPGA that you want to use and the HDL code that describes the behavior; here you define the FMC I/O pins, board-specific clock signals, timing constraints, etc. The constraints specific to the carrier are imported in the system_project.tcl file
system_top.v — contains everything about the HDL part of the project; it instantiates the system_wrapper module, IO buffers, I/ODDRs, modules that transform signals from LVDS to single-ended, etc. The I/O ports of this Verilog module will be connected to actual I/O pads of the FPGA.
- system_wrapper — is a tool generated file and can be found at <project_name>.srcs/sources_1/bd/system/hdl/system_wrapper.v
  - the I/O ports of this module are declared in either system_bd.tcl or in the board design file
  - this can be visualized in Vivado at the Block Design section
  - the base design, board design and system_bd.tcl describe this module, making the connections between the instantiated IPs

Project files for Intel boards#

A project for an Intel FPGA board should contain the following files:

Makefile — auto-generated file; contains all the IP dependencies needed for the project to be built
system_project.tcl — script that creates the actual Quartus project and runs the synthesis/implementation of the design. It also contains the I/O definitions for the interfaces between the board and the FPGA
system_qsys.tcl — also called platform designer; sources the base design first, then the board design, and afterwards it contains all the IP instances and connections that must be added on top of the sourced files, to complete the design of the project (these are specific to the combination of this carrier and board)
system_constr.sdc — contains clock definitions and other path constraints
system_top.v — contains everything about the HDL part of the project; it instantiates the system_wrapper module, IO buffers, I/ODDRs, modules that transform signals from LVDS to single-ended, etc. The I/O ports of this Verilog module will be connected to actual I/O pads of the FPGA

Examples#

Some carriers have a different name for these files, for example A10SoC has constraints file for both PL side and PS side:

a10soc_plddr4_assign.tcl — constraints file for the PL
a10soc_system_assign.tcl — constraints file for the PS

HDL	Linux Zynq	Actual Zynq	Linux ZynqMP	Actual ZynqMP	S10SoC	Linux Cyclone V	Actual Cyclone V
15	59	91	111	143	32	55	87
14	58	90	110	142	31	54	86
13	57	89	109	141	30	53	85
12	56	88	108	140	29	52	84
11	55	87	107	139	28	51	83
10	54	86	106	138	27	50	82
9	53	85	105	137	26	49	81
8	52	84	104	136	25	48	80
7	36	68	96	128	24	47	79
6	35	67	95	127	23	46	78
5	34	66	94	126	22	45	77
4	33	65	93	125	21	44	76
3	32	64	92	124	20	43	75
2	31	63	91	123	19	42	74
1	30	62	90	122	18	41	73
0	29	61	89	121	17	40	72

HDL	Linux Zynq	Actual Zynq	Linux ZynqMP	Actual ZynqMP	S10SoC	Linux Cyclone V	Actual Cyclone V
15	59	91	111	143	32	55	87
14	58	90	110	142	31	54	86
13	57	89	109	141	30	53	85
12	56	88	108	140	29	52	84
11	55	87	107	139	28	51	83
10	54	86	106	138	27	50	82
9	53	85	105	137	26	49	81
8	52	84	104	136	25	48	80
7	36	68	96	128	24	47	79
6	35	67	95	127	23	46	78
5	34	66	94	126	22	45	77
4	33	65	93	125	21	44	76
3	32	64	92	124	20	43	75
2	31	63	91	123	19	42	74
1	30	62	90	122	18	41	73
0	29	61	89	121	17	40	72

HDL	Linux Zynq	Actual Zynq	Linux ZynqMP	Actual ZynqMP	S10SoC	Linux Cyclone V	Actual Cyclone V
15	59	91	111	143	32	55	87
14	58	90	110	142	31	54	86
13	57	89	109	141	30	53	85
12	56	88	108	140	29	52	84
11	55	87	107	139	28	51	83
10	54	86	106	138	27	50	82
9	53	85	105	137	26	49	81
8	52	84	104	136	25	48	80
7	36	68	96	128	24	47	79
6	35	67	95	127	23	46	78
5	34	66	94	126	22	45	77
4	33	65	93	125	21	44	76
3	32	64	92	124	20	43	75
2	31	63	91	123	19	42	74
1	30	62	90	122	18	41	73
0	29	61	89	121	17	40	72