Application Note
AN_334
FT801 Polygon Application
Document Reference No.:FT_001075
Version 1.0
Issue Date: 2014-07-22
This document introduces the setup of the FT801 Polygon Application running on MSVC. The
objective of the Polygon Application is to enable users to become familiar with the usage of the
multi-touch functionality of FT801, the design flow, and the display list used to design the desired
user interface or visual effect.
Use of FTDI devices in life support and/or safety applications is entirely at the user’s risk, and the
user agrees to defend, indemnify and hold FTDI harmless from any and all damages, claims, suits
or expense resulting from such use.
Future Technology Devices International Limited (FTDI)
Unit 1, 2 Seaward Place, Glasgow G41 1HH, United Kingdom
Tel.: +44 (0) 141 429 2777 Fax: + 44 (0) 141 429 2758
Web Site: http://ftdichip.com
Copyright © 2014 Future Technology Devices International Limited
Application Note
AN_3344 FT801 Polygon Application
Version 1.0
Document Reference No.: FT_001075 Clearance No.: FTDI#382
Table of Contents
1
2
Introduction ................................................................................................................ 3
1.1
Overview .............................................................................................................. 3
1.2
Scope .................................................................................................................. 3
Application Flow ........................................................................................................... 4
2.1
3
Flowchart ............................................................................................................. 4
Description .................................................................................................................. 5
3.1
Intialization .......................................................................................................... 5
3.1.1
Set Extended mode for multitouch .................................................................... 5
3.1.2
Download the Bitmap ...................................................................................... 6
3.2
Functionality ......................................................................................................... 7
3.2.1
Read ctouch control registers ........................................................................... 7
3.2.2
Draw polygon ................................................................................................. 7
4
Conclusion................................................................................................................. 10
5
Contact Information ................................................................................................... 11
Appendix A– References .................................................................................................... 12
Document References .................................................................................................... 12
Acronyms and Abbreviations ........................................................................................... 12
Appendix B – List of Tables & Figures .................................................................................. 13
Appendix C– Revision History ............................................................................................. 14
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Application Note
AN_3344 FT801 Polygon Application
Version 1.0
Document Reference No.: FT_001075 Clearance No.: FTDI#382
1 Introduction
This application demonstrates the multi-touch functionality of the FT801 chip by drawing a polygon
on the screen, where the corners are defined by the points on the screen touched by the user.
The polygon created is used to lighten the selected area of a bitmap image.
Note: a maximum of 5 touch points may be used.
1.1 Overview
The document will provide a basic understanding of the FT801 multi-touch functionality.
The Arduino version of the application requires an SD card to read and load the bitmaps. The
bitmaps must be copied from the Test folder to the SD card root folder.
1.2 Scope
This document can be used by software programmers to develop GUI applications using the FT801
with any MCU via SPI.
For information on how to use the project file and source code, refer to the following application
note: FT_App_Gradient Application note
Note that detailed documentation is available at www.ftdichip.com/EVE.htm including:
FT801 Datasheet
FT800 Series Programming Guide
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Application Note
AN_3344 FT801 Polygon Application
Version 1.0
Document Reference No.: FT_001075 Clearance No.: FTDI#382
2
Application Flow
2.1 Flowchart
Figure 2-1 Flowchart
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Application Note
AN_3344 FT801 Polygon Application
Version 1.0
Document Reference No.: FT_001075 Clearance No.: FTDI#382
3 Description
The parameters which need to be initialized when constructing the display list are detailed below.
3.1 Intialization
3.1.1 Set Extended mode for multitouch
By default, the FT801 touch engine works in compatibility mode and in this mode only one touch
point is detected (in order to be backward-compatible with the FT800). In extended mode, the
FT801 touch engine can detect up to 5 touch points simultaneously.
Before entering in extended mode, user needs to do calibration in compatibility mode.
A co-processor command list is started. This command will clear the display parameters.
Ft_Gpu_CoCmd_Dlstart(phost);
Ft_App_WrCoCmd_Buffer(phost,CLEAR(1,1,1));
The following commands set the colour and then print a text message to the user which tells them
to tap on the dots during the following calibration routine. The FT800’s built-in calibration routine
is then called.
Ft_App_WrCoCmd_Buffer(phost,COLOR_RGB(255,255,255));
Ft_Gpu_CoCmd_Text(phost,FT_DispWidth/2,FT_DispHeight/2,28,OPT_CENTERX|OPT_CENTERY,"Ple
ase tap on a dot");
Ft_Gpu_CoCmd_Calibrate(phost,0);
The display list is then terminated and swapped to allow the changes to take effect.
Ft_App_WrCoCmd_Buffer(phost,DISPLAY());
Ft_Gpu_CoCmd_Swap(phost);
Ft_App_Flush_Co_Buffer(phost);
Ft_Gpu_Hal_WaitCmdfifo_empty(phost);
Figure 3-1 Calibration screen
As this application is designed to demonstrate FT801’s multitouch functionality, it is necessary to
set the mode to extended. For more information, refer to the FT800 Series Programming Guide
(see Appendix A– References).
Ft_Gpu_Hal_Wr8(phost, REG_CTOUCH_EXTENDED, CTOUCH_MODE_EXTENDED);
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Application Note
AN_3344 FT801 Polygon Application
Version 1.0
Document Reference No.: FT_001075 Clearance No.: FTDI#382
3.1.2 Download the Bitmap
This application uses one bitmap, which will be in the background. The bitmap is downloaded into
the desired location in the FT801’s Graphics RAM. The bitmap handles are also assigned here.
After downloading the bitmap into the FT801, it will be present in the background, as shown in the
following screenshot:
Figure 3-2 Bitmap loaded in background
The application then uses the COLOR_RGB command to set the red, green and blue values of the
FT801 colour buffer, which will be applied to the downloaded image. The following screenshot
shows the resulting effect on the bitmap image.
Ft_App_WrCoCmd_Buffer(phost, COLOR_RGB(0x40,0x40,0x40));
Figure 3-3 Bitmap after COLOR_RGB command
Note: These commands, followed by a swap display list command, must then be sent to the FT801
using the Flush command. See the provided sample project for the full code listing.
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Application Note
AN_3344 FT801 Polygon Application
Version 1.0
Document Reference No.: FT_001075 Clearance No.: FTDI#382
3.2 Functionality
The Polygon Demo is an interactive demonstration where the user can touch the screen with a
maximum of 5 touch points simultaneously. This section shows the steps taken to detect the touch
and display the polygon.
3.2.1 Read ctouch control registers
As the FT801 has a different touch engine and touch control registers compared to the FT800, and
is capable of detecting upto 5 simultaneous touches, the application needs to read the 5 ctouch
registers. The code below shows this:
ft_void_t read_extended(ft_int16_t sx[5], ft_int16_t sy[5])
{
ft_uint32_t sxy0, sxyA, sxyB, sxyC;
sxy0 = Ft_Gpu_Hal_Rd32(phost, REG_CTOUCH_TOUCH0_XY);
sxyA = Ft_Gpu_Hal_Rd32(phost, REG_CTOUCH_TOUCH1_XY);
sxyB = Ft_Gpu_Hal_Rd32(phost, REG_CTOUCH_TOUCH2_XY);
sxyC = Ft_Gpu_Hal_Rd32(phost, REG_CTOUCH_TOUCH3_XY);
sx[0]
sy[0]
sx[1]
sy[1]
sx[2]
sy[2]
sx[3]
sy[3]
=
=
=
=
=
=
=
=
sxy0 >>
sxy0;
sxyA >>
sxyA;
sxyB >>
sxyB;
sxyC >>
sxyC;
16;
16;
16;
16;
sx[4] = Ft_Gpu_Hal_Rd16(phost,REG_CTOUCH_TOUCH4_X);
sy[4] = Ft_Gpu_Hal_Rd16(phost,REG_CTOUCH_TOUCH4_Y);
}
3.2.2 Draw polygon
To draw the polygon, the application reads the touch co-ordinates in a loop. After reading the
coordinates, it calculates the angles based on these co-ordinates, using the atan8 and atan2
functions.
To draw the polygon itself, the application first uses the COLOR_MASK to disable writing of the
colour components. It then uses the STENCIL_OP and STENCIL_FUNC commands to fill the drawn
polygon with color. This is done by the code below:
Ft_App_WrCoCmd_Buffer(phost,(COLOR_MASK(0,0,0,0)));
Ft_App_WrCoCmd_Buffer(phost,STENCIL_OP(KEEP, INVERT));
Ft_App_WrCoCmd_Buffer(phost,STENCIL_FUNC(ALWAYS, 255, 255));
It then uses the EDGE_STRIP_B and SCISSOR_XY commands to draw the polygon:
ft_void_t poly_paint() {
poly_x0 = max(0, poly_x0);
poly_y0 = max(0, poly_y0);
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Application Note
AN_3344 FT801 Polygon Application
Version 1.0
Document Reference No.: FT_001075 Clearance No.: FTDI#382
poly_x1 = min(16 * 480, poly_x1);
poly_y1 = min(16 * 272, poly_y1);
Ft_App_WrCoCmd_Buffer(phost,SCISSOR_XY(poly_x0, poly_y0));
Ft_App_WrCoCmd_Buffer(phost,SCISSOR_SIZE(poly_x1 - poly_x0 + 1, poly_y1 poly_y0 + 1));
Ft_App_WrCoCmd_Buffer(phost,BEGIN(EDGE_STRIP_B));
poly_perim();
}
The screenshot below shows when the user has touched 3 points.
Figure 3-4 Polygon drawn with 3 points
To draw the outline for the polygon, the application uses the LINE_WIDTH, LINE_STRIP and
VERTEX_2F functions, as shown below:
Ft_App_WrCoCmd_Buffer(phost,RESTORE_CONTEXT());
Ft_App_WrCoCmd_Buffer(phost, COLOR_RGB(0x80,0x80,0xff));
Ft_App_WrCoCmd_Buffer(phost, LINE_WIDTH(24));
poly_outline();
ft_void_t poly_perim() {
for (j = 0; j < poly_n; j++)
Ft_App_WrCoCmd_Buffer(phost,VERTEX2F(poly_x[j], poly_y[j]));
Ft_App_WrCoCmd_Buffer(phost,VERTEX2F(poly_x[0], poly_y[0]));
}
ft_void_t poly_outline() {
Ft_App_WrCoCmd_Buffer(phost,BEGIN(LINE_STRIP));
poly_perim();
}
When the user touches the screen with 3 points, the outline is drawn as shown below.
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Application Note
AN_3344 FT801 Polygon Application
Version 1.0
Document Reference No.: FT_001075 Clearance No.: FTDI#382
Figure 3-5 Polygon outline drawn
The screenshot below shows the application with 5 simultaneous touches:
Figure 3-6 Polygon drawn with 5 touch points
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AN_3344 FT801 Polygon Application
Version 1.0
Document Reference No.: FT_001075 Clearance No.: FTDI#382
4 Conclusion
This application has demonstrated the configuration of the FT801 for multi-touch operation and
has also presented an example of the way in which the multi-touch capabilities can be used. The
techniques shown here can be used to add a multi-touch interface to a wide variety of
applications.
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AN_3344 FT801 Polygon Application
Version 1.0
Document Reference No.: FT_001075 Clearance No.: FTDI#382
5 Contact Information
Head Office – Glasgow, UK
Branch Office – Tigard, Oregon, USA
Future Technology Devices International Limited
Unit 1, 2 Seaward Place, Centurion Business Park
Glasgow G41 1HH
United Kingdom
Tel: +44 (0) 141 429 2777
Fax: +44 (0) 141 429 2758
Future Technology Devices International Limited
(USA)
7130 SW Fir Loop
Tigard, OR 97223-8160
USA
Tel: +1 (503) 547 0988
Fax: +1 (503) 547 0987
E-mail (Sales)
E-mail (Support)
E-mail (General Enquiries)
[email protected]
[email protected]
[email protected]
E-Mail (Sales)
E-Mail (Support)
E-Mail (General Enquiries)
[email protected]
[email protected]
[email protected]
Branch Office – Taipei, Taiwan
Branch Office – Shanghai, China
Future Technology Devices International Limited
(Taiwan)
2F, No. 516, Sec. 1, NeiHu Road
Taipei 114
Taiwan , R.O.C.
Tel: +886 (0) 2 8791 3570
Fax: +886 (0) 2 8791 3576
Future Technology Devices International Limited
(China)
Room 1103, No. 666 West Huaihai Road,
Shanghai, 200052
China
Tel: +86 21 62351596
Fax: +86 21 62351595
E-mail (Sales)
E-mail (Support)
E-mail (General Enquiries)
E-mail (Sales)
E-mail (Support)
E-mail (General Enquiries)
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
Web Site
http://ftdichip.com
Distributor and Sales Representatives
Please visit the Sales Network page of the FTDI Web site for the contact details of our distributor(s) and sales
representative(s) in your country.
System and equipment manufacturers and designers are responsible to ensure that their systems, and any Future Technology
Devices International Ltd (FTDI) devices incorporated in their systems, meet all applicable safety, regulatory and system-level
performance requirements. All application-related information in this document (including application descriptions, suggested
FTDI devices and other materials) is provided for reference only. While FTDI has taken care to assure it is accurate, this
information is subject to customer confirmation, and FTDI disclaims all liability for system designs and for any applications
assistance provided by FTDI. Use of FTDI devices in life support and/or safety applications is entirely at the user’s risk, and the
user agrees to defend, indemnify and hold harmless FTDI from any and all damages, claims, suits or expense resulting from
such use. This document is subject to change without notice. No freedom to use patents or other intellectual property rights is
implied by the publication of this document. Neither the whole nor any part of the information contained in, or the product
described in this document, may be adapted or reproduced in any material or electronic form without the prior written consent
of the copyright holder. Future Technology Devices International Ltd, Unit 1, 2 Seaward Place, Centurion Business Park,
Glasgow G41 1HH, United Kingdom. Scotland Registered Company Number: SC136640
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Application Note
AN_3344 FT801 Polygon Application
Version 1.0
Document Reference No.: FT_001075 Clearance No.: FTDI#382
Appendix A– References
Document References
1. FT800 Series programmer guide
2. FT801 Embedded Video Engine Datasheet
3. Polygon App
Acronyms and Abbreviations
Terms
Description
SPI
Serial Peripheral Interface
GUI
Graphical User Interface
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Application Note
AN_3344 FT801 Polygon Application
Version 1.0
Document Reference No.: FT_001075 Clearance No.: FTDI#382
Appendix B – List of Tables & Figures
Figure 2-1 Flowchart .................................................................................................. 4
Figure 3-1 Calibration screen ..................................................................................... 5
Figure 3-2 Bitmap loaded in background .................................................................... 6
Figure 3-3 Bitmap after COLOR_RGB command .......................................................... 6
Figure 3-4 Polygon drawn with 3 points ..................................................................... 8
Figure 3-5 Polygon outline drawn .............................................................................. 9
Figure 3-6 Polygon drawn with 5 touch points ........................................................... 9
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Application Note
AN_3344 FT801 Polygon Application
Version 1.0
Document Reference No.: FT_001075 Clearance No.: FTDI#382
Appendix C– Revision History
Document Title:
AN_334 FT801 Polygon Application
Document Reference No.:
FT_001075
Clearance No.:
FTDI#402
Product Page:
http://www.ftdichip.com/FTProducts.htm
Document Feedback:
Send Feedback
Revision
1.0
Changes
Initial release
Date
2014-07-22
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