GOWIN IPUG903-3.0E Scaler IP User Guide

Gowin Scaler IP
User Guide

IPUG903-3.0E Scaler IP

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Disclaimer
GOWINSEMI assumes no liability and provides no warranty (either expressed or implied) and is not responsible for any damage incurred to your hardware, software, data, or property resulting from usage of the materials or intellectual property except as outlined in the GOWINSEMI Terms and Conditions of Sale. GOWINSEMI may make changes to this document at any time without prior notice. Anyone relying on this documentation should contact GOWINSEMI for the current documentation and errata.
Revision History

⚫ Port description updated.
⚫ Parameter description updated.
3/7/2022| 3.0E| ⚫ Removed output buffer to reduce BSRAM resource
⚫ Extended input line buffer depth, up to 4096.
⚫ Removed Bicubic 6 tap algorithm.

About This Guide

1.1 Purpose
The purpose of Gowin Scaler IP User Guide is to help you learn the features and usage of Gowin Scaler IP by providing the descriptions of functions, ports, timing, configuration and call, reference design.
1.2 Related Documents
The user guides are available on the GOWINSEMI Website. You can find the related documents at www.gowinsemi.com:

1.  DS100, GW1N series of FPGA Products Data Sheet
2. DS117, GW1NR series of FPGA Products Data Sheet
3.  DS102, GW2A series of FPGA Products Data Sheet
4. DS226, GW2AR series of FPGA Products Data Sheet
5. DS961, GW2ANR series of FPGA Products Data Sheet
6. DS971, GW2AN-18X & 9X Data Sheet
7.  DS976, GW2AN-55 Data Sheet

8. SUG100, Gowin Software User Guide
1.3 Terminology and Abbreviations
Table 1-1 shows the abbreviations and terminology used in this manual.
Table 1-1 Abbreviations and Terminology

1.1    Support and Feedback
Gowin Semiconductor provides customers with comprehensive technical support. If you have any questions, comments, or suggestions, please feel free to contact us directly by the following ways.
Website: www.gowinsemi.com  
E-mail: support@gowinsemi.com

Overview

2.1 Overview
Gowin Scaler IP is used to convert the input video images from one resolution Xin Yin to another output resolution Xout Yout. Resolution parameters can be preset in the IP configuration interface or dynamically configured in real time. In addition, interpolation algorithms supported by Scaler IP include nearest neighbor, bilinear and bicubic.
Gowin Scaler IP supports real-time video signal input and memory interface video signal input, and both input and output data interfaces are parallel video signals.
Table 2-1 Gowin Scaler IP

Gowin Scaler IP

Logic Resource| Please refer to Table 2-2.
Delivered Doc.
Design Files| Verilog (encrypted)
Reference Design| Verilog
TestBench| Verilog
Test and Design Flow
Synthesis Software| GowinSynthesis
Application Software| Gowin Software (V1.9.8.05 and above)

2.1 Key Features

• Supports single, YCbCr422, YCbCr444 and RGB video format
• Supports parallel input
• Supports dynamic configuration of scale parameters
• Supports nearest neighbor, bilinear and bicubic algorithms
• The vertical and horizontal support 4 taps (for Bicubic only)
• The vertical and horizontal coefficients support 8, 16 and 32 phases (for Bicubic only)
• Image data supports 8,10, 12 bits width
• Filter coefficient supports 9~16 bits width
• Supports input and output resolution range from 32 x 32 to 4096 x 4096

2.1 Resource Utilization

Gowin Scaler IP employs Verilog. Its performance and resource utilization may vary when the design is employed in different devices, or at different densities, speeds, or grades. Taking GW1N-9 and GW2A-18 series of FPGA devices as an instance, Table 2-2 presents an overview of the resource utilization. GW1N only supports nearest neighbor and bilinear algorithms. For the applications in other Gowin FPGA devices, please see the later release information.
Table 2-2 Resource Utilization

800×600 to 1280×720
Video Format| YC444| YC444| YC444| YC444
Tapsize| 2×2| 2×2| 2×2| 4×4
Data Bit Width| 8| 8| 8| 8
Coefficient Bit Width| 16| 16| 16| 16
Resisters| 933(17%)| 933(17%)| 926(5%)| 1774(11%)
LUTs| 738(10%)| 738(10%)| 735(3%)| 1478(7%)
BSRAMs| 12(46%)| 12(46%)| 12(26%)| 24(52%)
MULT18x18| 0/0/20| 12/12/20| 12/12/48| 24/24/48

Functional Description

3.1    System Diagram
Gowin Scaler IP is used to receive video signals for scale in Live mode or video data in Memory mode. The input and output data interfaces are all video standard parallel signals, and the control interface is scale parameter signal.
Figure 3-1 System Block Diagram

3.2 Block Diagram

Figure 3-3 Block Diagram (Memory mode)

Scaler IP includes parameter definition module, mode control module and scale core module, among which the scale core module includes vertical calculation sub-module, horizontal calculation sub-module, row calculation control state machine sub-module and output row buffer sub-module, realizing video image scale function via mutual cooperations among these modules.

1.  Parameter Definition Module
   The Scaler parameters include video format, data source, data bit width, video resolution of input and output, and dynamic configuration.

2. Mode Control Module
   Frame synchronization and data enable signals for input and output are configured based on the input video source type, defined parameters, and input and output data buffer status.

3. Scale Core Module
   According to the input and output video resolution parameters, the live image scale operation is completed and output, and the empty and full state of the data buffer is output also. This module includes four sub-modules: vertical calcualtion sub-module, horizontal calculation sub-module, row calculation control state machine sub-module, and output row buffer sub-module.
   a). The functions completed by vertical calculation sub-module include vertical coordinate conversion, vertical calculation coefficient generation, vertical calculation data generation, vertical multiplication and addition processing, etc.
   b). The functions completed by horizontal calculation sub-module  include horizontal coordinate conversion, horizontal calculationcoefficient generation, horizontal calculation data generation, horizontal multiplication and addition processing, etc.
   c). According to the state of each module, the row calculation control state machine sub-module generates row calculation enable signal, controlling the vertical calculation sub-module and the horizontal calculation sub-module for calculation.
   d). The output row buffer sub-module will buffer the final calculated data into this sub-module and output the scaled data according to the data output request.

Finally, the calcualted pixel of the target image is output to the output row buffer, then is output according to the parallel video data format with VS, DE and DATA.
Depending on the input video format, set the number of scale core and signal type.
Depending on the type of input signal source, Scaler IP can be set to two modes, Live mode and Memory mode.
3.3.1 Live Mode

The estimation formula of minimum output pixel clock and system working clock frequency in Live mode is as follows.
Minfout = (OutWidthOutHeight) / (InHeight/fhs) 1.1
Note!

• fhs represents the input video line frequency
• “1.1” represents 10% margin increase
  Minfsys = 1.05 fin (MaxWidthTotal*SRver)/(InWidthTotal+InHblank)

Notes!

• SRver means that vertical scaling multiple is rounded.
• MaxWidthTotal means a larger total of input or output.
  Example 1: Zoom in 640×480@60hz to 1920×1080@60hz fhs = 31.5KHz，fin = 27MHz，SRver = round_up(1080/480) = 3
  InWidthTotal+InHblank = 857 + 217 = 1074
  MaxWidthTotal = 2200
  Minfout = (19201080)/(480/31500)1.1 = 149.69MHz
  Minfsys = 1.0527MHz(22003)/1074 = 174.22MHz
  Example 2: Zoom out 1920×1080@60hz to 1280×720@60hz
  fhs = 67.5KHz，fin = 148.5MHz，SRver = round_up(720/1080) = 1
  InWidthTotal+InHblank = 2200 + 280 = 2480
  MaxWidthTotal = 2200
  Minfout = (1280720)/(1080/67500)1.1 = 63.36MHz
  Minfsys = 1.05148.5MHz(22001)/2480 = 138.32MHz
  In addition, the estimation formule of system clock frequency and input video clock frequency is as follows: clk sys  )( ZoomLevel sr   clkvin  When zooming out , sr<1, the sys_clk and out_clk frequency only need to be slightly higher than the input clock when zooming out in live mode, or even using the input clock.
  However, when zooming in in Live mode, especially when the magnification times is large, sys_clk is highly required, and this mode is not recommended.

3.3.2 Memory Mode
Figure 3-5 Memory Mode Diagram

The estimation formula of minimum input and output pixel clock in memory mode is as follows, and the system clock takes the larger of the two.
fin>= Hintotal Vintotal finvs
fout>= Houttotal Vouttotal foutvs
This clock frequency is the pixel clock frequency of each resolution in VESA standard, and the user can refer to VESA.
Since the system clock only needs to take the input/output pixel frequency higher than this frequency in Memory mode, the system clock will not be required highly. So Memory mode is suitable for zooming in.

Port List

The 10 port of Gowin Scaler IP is shown in Figure 4-1.
Ports may vary slightly depending on the configuration parameters.
The IO port of Gowin Scaler IP is shown in Table 4-1
Table 4-1 Gowin CSC IP Ports List .

IP as reference.
2| I_sysclk| I| System working clock
3| I_param_update| I| This signal is valid when dynamic control is
| | | enabled.
| | | Parameter updated enable signal,
| | | active-high, which requires at least 200ns.
4| I_vin_hsize| I| This signal is valid when dynamic control is
| | | enabled.
| | | Input horizontal resolution of the image.
5| I_vin_vsize| I| This signal is valid when dynamic control is
| | | enabled.
| | | Input vertical resolution of the image.
6| I_vout_hsize| I| This signal is valid when dynamic control is
| | | enabled.Output horizontal resolution of the
| | | image.
7| I_vout_vsize| I| This signal is valid when dynamic control is
| | | enabled.
| | | Output vertical resolution of the iamge.
8| I_hor_skfactor| I| This signal is valid when dynamic control is
| | | enabled. Horizontal scale factor, unsigned
| | | fixed-point number. Above 8 bits represents
| | | integer, and below 16 bits represents
| | | decimal.
| | | The formula = (input horizontal
| | | resolution/output horizontal
| | | resolution)(2^16).
9| I_ver_skfactor| I| This signal is valid when dynamic control is
| | | enabled. Vertical scale factor, unsigned
| | | fixed-point number. Above 8 bits represents
| | | integer, and below 16 bits represents
| | | decimal.
| | | The formula = (input vertical
| | | resolution/output vertical resolution)(2^16)
10| I_vin_clk| I| Video input pixel clock
11| I_vin_ref_vs| I| Input the reference field synchronization vs
| | | signal.
| | | When selecting Live mode, this signal is
| | | invalid.
| | | When selecting Memory mode, connect to
| | | vs signal of synchronous timing generation
| | | module.
12| I_vin_ref_de| I| Input reference data enable de signal.
| | | When selecting Live mode, this signal is
| | | invalid.
| | | When selecting Memory mode, connect to
| | | de signal of synchronous timing generation
| | | module.
13| O_vin_vs_req| O| Output field synchronization vs request signal.
No.| Signal Name| I/O| Description| Notes
---|---|---|---|---
| | | When selecting Live mode, this signal is invalid.
When selecting Memory mode, connect to vs request signal of frame buffer module.|
14| O_vin_de_req| O| Output data enable de request signal. When selecting Live mode, this signal is invalid.
When selecting Memory mode, connect to de request signal of frame buffer module.
15| I_buff_ready| I| Front-end input buff valid signal.
When selecting Live mode, this signal is invalid.
When selecting Memory mode, connect to frame buffer fifo status signal.
16| I_up_down_sel| I| This signal is valid when dynamic control is enabled and when Memory mode is selected.
Zoom in or out the selection signal: 0 represents zooming in; 1 represents zooming out;
17| I_vin_vs_cpl| I| Input field synchronization vs signal. When selecting Live mode, connect to the input video vs signal.
When selecting Memory mode, this signal is invalid.
18| I_vin_de_cpl| I| Actual input data enable de signal.
When selecting Live mode, connect to the input video de signal.
When selecting Memory mode, connect to frame buffer module output de signal.
19| I_vin_data0_cpl| I| Channel 0 input video data signal.
When selecting Live mode, connect to the input video data signal.
When selecting Memory mode, connect to the output data signal of frame buffer module.
When the video format is YC422, it is the Y component.
20| I_vin_data1_cpl| I| Channel 1 input video data signal.
When selecting Live mode, connect to the input video data signal.
When selecting Memory mode, connect to the output data signal of frame
uffer  module.When the video format is YC422, it is the C component.
21| I_vin_data2_cpl| I| Channel 2 input video data signal.
When selecting Live mode, connect to the
No.| Signal Name| I/O| Description| Notes
---|---|---|---|---
| | | input video data signal.

When selecting Memory mode, connect to the output data signal of frame buffer module.

|
22| I_vout_clk| I| Video output pixel clock
23| O_vout_vs| O| Output video field synchronization vs signal
24| O_vout_de| O| Output video data enable de signal
25| O_vout0_data| O| Channel 0 output video data signal. When the video format is YC422, it is the Y component.
26| O_vout1_data| O| Channel 1 output video data signal. When the video format is YC422, it is the C component.
27| O_vout2_data| O| Channel 2 output video data signal.
28| O_vval_de| O| Debug option, vertical calculation output de signal.
29| O_vval_data0| O| Debug option, vertical calculation ouput data signal.
30| O_vval_data1| O| Debug option, vertical calculation ouput data signal.
31| O_vval_data2| O| Debug option, vertical calculation ouput data signal.

Parameter Configuration

Table 5-1 Scaler Parameter

width of input/output image pixel
2| **** Coefficient Width| 9~16| 16| Interpolation calculation coefficient bus width;
The highest 1bit for sign, 1bit for integer and the remainder for decimal place
3| Parameter Dynamic Control| Yes，No| Yes| Parameter dynamic configuration enable
3| Input Frame Width| 32~4096| 1024| Static input image horizontal resolution is valid when PARAM_DYNAMIC_CTRL is No.
4| Input Frame Height| 32~4096| 68| Static input image vertical resolution is valid when PARAM_DYNAMIC_CTRL is No.
**** 5| Output Frame Width| 32~4096| 1024| Static output image horizontal resolution is valid when PARAM_DYNAMIC_CTRL is No.
6| Output Frame Height| 32~4096| 68| Stativ output image vertical resolution is valid when ; When PARAM_DYNAMIC_CTRL is No.
**** 7| Video Format| Single YC422, RGB or YC444| **** RGB or YC444| Video format selecting; Single: Single color component;
YC422: The format of YCbCr 4:2:2 and inputs Y component and Cb/Cr component.

Timing Description

This chapter describes the timing of Gowin Scaler IP.
The timing requirement of I_param_update is as shown in Figure 6-1.
Figure 6-1 Timing Diagram of I_param_update

The timing diagram of Live mode is as shown in Figure 6-2. The timing diagram of Memory mode is as shown in Figure 6-3.
Figure 6-3 Timing Diagram of Memory Mode

Interface Configuration

Users can use IP core generator tool in the IDE to call and configure
Gowin Scaler IP.

1. Open IP Core Generator
   After creating the project, click the “Tools” tab in the upper left, select and open the IP Core Generater from the drop-down list, as shown in Figure 7-1.

2.   Open Scaler IP Core
   Click “Multimedia” option and double-click on “Scaler” to open the configuration interface, as shown in Figure 7-2.![GOWIN IPUG903-3.0E Scaler IP

• IP Core](https://manuals.plus/wp-content/uploads/2023/08/GOWIN-IPUG903-3.0E- Scaler-IP-IP-Core.jpg)

  3. Open Scaler IP Core
     On the left of the configuration interface is the port diagram of Scaler IP core, as shown in Figure 7-3.

  4. Configuration Information
     See the project basic information on the configuration interface. Take GW2A-18-PBGA484 as an example, the top-level file name of the generated project is shown in the “Module Name”, and the default is “Scaler_Top”, which can be modified by users. The file generated by the IP core is shown in “File Name”, and the default is “scaler”. It can be modified  by users. The “Creat IN” option shows the IP core files path, and the defaultis \project path\src\scaler. It can be modified by users.

  5. Data Options
     In the Data Options tab, users need to configure the algorithm, data bit width, resolution and other parameter information used by Scaler operations.

Reference Design

This chapter focuses on the usage and constructure of the reference design of Scaler IP. Please see the Scaler Reference Design for details at Gowinsemi website.
8.1 Design Instance Application
Taking DK-VIDEO-GW2A18-PG484 as an example, the block diagram is as shown in Figure 8-1. For the details of DK-VIDEO-GW2A18-PG484, you can click here. In the above reference design example, Scaler IP selects the Live mode, and its steps are as follows:

1. The test pattern module is used to generate the test pattern with 1024×768 resolution and RGB888 data format.
2. Call Scaler IP core generator to generate Scaler module and zoom out the image from 1024×768 to 800×600.
3. The shrunk image data is written to the DDR3 buffer.
4. Then read from DDR3 with 1280×720 resolution. Finally, the display is output to the monitor through the HDMI2 TX interface of the development board.

When the reference design is applied to the board level test, users can convert the output data via the video encoding chip and output it to the display or observe the data with the online logic analyzer or oscilloscope. In the simulation project provided by the reference design, BMP is used as the test excitation source. tb_top is the top-level module of the simulation project. The simulation results can be compared with the output figures
8.2 Design Instance Application
Taking DK-VIDEO-GW2A18-PG484 as an example, the block diagram is as shown in Figure 8-2. In the above design example, Scaler IP selects Memory mde, and the steps are as follows:

1. The test pattern module is used to generate the test pattern with 800×600 resolution and RGB888 data format.
2.  The generated image data is written to the DD R3 buffer.
3. Call Scaler IP core generator to generate Scaler module and zoom in the image from 1280×720 to1920x1080。
4. Because scale is generated by standard timing in Memory mode, the scaled data can be output and displayed. Finally, the display is output to the monitor through the HDMI2 TX interface of the development board.

When the reference design is applied to the board level test, users can convert the output data via the video encoding chip and output it to the display or observe the data with the online logic analyzer or oscilloscope. In the simulation project provided by the reference design, BMP is used as the test excitation source. tb_top is the top-level module of the simulation project. The simulation results can be compared with the output figures.

File Delivery

The delivery file of Gowin Scaler IP includes document, design source code and reference design.
9.1 Document
The document mainly includes the user guide.
Table 9-1 Documents List

9.2 Design Source Code (Encryption)
The encrypted code file includes the Gowin Scaler IP RTL encrypted code which is used for GUI in order to cooperate with Gowin software to generate the IP core required by users.
Table 9-2 Design Source Code List

interface
information, encrypted.

9.3 Reference Design
Gowin_Scaler_Live_RefDesign folder includes the netlist file of Gowin Scaler IP, user reference design, constraints file, top-level file and the project file, etc.
Table 9-3 Gowin_Scaler_Live_RefDesign src File List

Gowin_Scaler_Memory_RefDesign folder mainly contains netlist files, user reference designs, constraint files, top-level files and project folders for the Gowin Scaler IP.
Table 9-4 Gowin_Scaler_Memory_RefDesign src File List

Name

|

Description

---|---
scaler_test_top.v| The top module of reference design
testpattern.v| Test pattern generation module
scaler_test_top.cst| Project Physical Constraints File
scaler_ref_design_live.sdc| Project Timing Constraints File
scaler| Scaler IP project folder
scaler.v| Scaler IP top-level file generated (encryptied)
scaler.vo| Scaler IP netlist file generated for simulation usage
ddr3_memory_interface| DDR3 Memory Interface IP project folder
video_frame_buffer| Frame buffer module project folder
gowin_rpll| PLL IP project folder
syn_code| Synchronous timing module project folder
i2c_master| I2C Master IP project folder
adv7513_iic_init.v| ADV7513 chip initialization module

References

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