APPLICATION NOTE
AN_269
FT_APP_SIGNATURE
Version 1.2
Document Reference No.: FT_000914
Issue Date: 2014-06-30
This document is to introduce the Signature Demo. The objective of the Demo Application is to
enable users to become familiar with the usage of the FT800 series, the design flow, and 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_269 FT_App_Signature
Version 1.2
Document Reference No.: FT_000914 Clearance No.: FTDI# 364
Table of Contents
1
2
3
Introduction ................................................................................................................ 3
1.1
Overview .............................................................................................................. 3
1.2
Scope .................................................................................................................. 3
Display Requirements ................................................................................................... 4
2.1
Signature Area ...................................................................................................... 4
2.2
Button ................................................................................................................. 4
2.3
Background .......................................................................................................... 4
Design Flow ................................................................................................................. 5
3.1
4
Signature Flowchart ............................................................................................... 6
Description of the Functional Blocks ................................................................................ 7
4.1
System Intialization ............................................................................................... 7
4.2
Info() ................................................................................................................... 8
4.3
Home_setup()....................................................................................................... 9
4.4
Signature() ......................................................................................................... 10
4.4.1
FT801 Signature ........................................................................................... 12
5
Operation of the Application ........................................................................................ 13
6
Contact Information ................................................................................................... 14
Appendix A– References .................................................................................................... 15
6.1
Document References .......................................................................................... 15
6.2
Acronyms and Abbreviations ................................................................................. 15
Appendix B – List of Tables & Figures .................................................................................. 16
6.3
List of Figures ..................................................................................................... 16
Appendix C– Revision History ............................................................................................. 17
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Copyright © 2014 Future Technology Devices International Limited
Application Note
AN_269 FT_App_Signature
Version 1.2
Document Reference No.: FT_000914 Clearance No.: FTDI# 364
1 Introduction
This design example demonstrates an interactive user interface that provides a signature area,
useful for payment terminals. The touch screen is used to capture handwriting inside of the
signature area. The touch events are then drawn within the signature area interactively. While
the signature area is active, an array of stars is drawn in a moving pattern behind the signature
area. A button then clears the signature area, ready for another signature.
1.1 Overview
The document will provide information on drawing graphics elements through primitives, tagging
of touch capabilities and the structure of display lists. In addition, this application note outlines
the general steps of the system design flow, display list creation and integrating the display list
with the system host microcontroller.
The source code for this application is provided in section 4 or at:
http://www.ftdichip.com/Support/SoftwareExamples/FT800_Projects.htm
1.2 Scope
This document can be used as a guide by designers to develop GUI applications by using FT800
with any MCU via SPI or I2C. Note that detailed documentation is available on
www.ftdichip.com/EVE.htm, including:
FT800 datasheet
FT801 datasheet
Programming Guide covering EVE command language
AN_240 FT800 From the Ground Up
AN_245 VM800CB_SampleApp_PC_Introduction - covering detailed design flow with a PC
and USB to SPI bridge cable
AN_246 VM800CB_SampleApp_Arduino_Introduction – covering detailed design flow in an
Arduino platform
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Application Note
AN_269 FT_App_Signature
Version 1.2
Document Reference No.: FT_000914 Clearance No.: FTDI# 364
2 Display Requirements
This section describes some of the key components of the design.
2.1 Signature Area
The signature area uses the display and touch screen. As the touch screen is written upon, the
corresponding pixels in the signature area are rendered out to simulate drawing on a page. The
signature area only covers a portion of the screen. Touch events outside of this area are ignored.
2.2 Button
A second touch area uses a FT800 button widget. When touched, any information drawn in the
signature area is cleared out.
2.3 Background
While the signature and button areas are active, an array of animated stars is drawn behind the
active touch areas.
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Application Note
AN_269 FT_App_Signature
Version 1.2
Document Reference No.: FT_000914 Clearance No.: FTDI# 364
3 Design Flow
Every EVE design follows the same basic principles as highlighted in Figure 3.1.
Select and configure your host port for controlling the FT800 then wake the device before
configuring the display. The creative part then revolves around the generation of the display list,
“** APPLICATION DATA **” in the figure below. There will be two lists. The active list and the
updated/next list are continually swapped to render the display. Note, header files map the
pseudo code of the design file of the display list to the FT800 instruction set, which is sent as the
data of the SPI (or I²C) packet (typically <1KB). As a result, with EVE's object oriented approach,
the FT800 is operating as an SPI peripheral while providing full display, audio, and touch
capabilities.
Hardware
SPI or I2C
GPIO for PD_n
Interrupt Input
Select MCU
Select Display,
Audio & Touch
Size = WQVGA, QVGA, up to 512 x 512
Resistive Touch
Audio Amplifier
Software
Configure MCU
Interface
SPI Mode Zero -or- I2C Address
Set Host MCU SPI Speed to 10MHz maximum
Little Endian Data Format
Wake-up
FT800
Toggle PD_n low for 20ms min., then high
Write 0x00, 0x00, 0x00 to wake FT800
Write 0x44, 0x00, 0x00 to select Ext Clock
Write 0x62, 0x00, 0x00 to select 48MHz
Host MCU SPI Speed can now go up to 30MHz
REG_PCLK = zero until after display parameters are set
Configure
Display
Set Screen Registers
Vertical – REG_VCYCLE, REG_VSIZE, REG_VSYNC0/1, REG_VOFFSET
Horizontal – REG_HCYCLE, REG_HSIZE, REG_HSYNC0/1, REG_HOFFSET
Configure
Touch and
Audio
Set Touch Registers
REG_TOUCH_MODE, REG_TOUCH_RZTHRESH, Others if necessary
Set Audio Register
REG_VOL_SOUND = zero
Write Initial
Display List &
Enable Display
Write
Application
Display List
Swap Display
LIsts
CLEAR_COLOUR_RGB(0,0,0)
CLEAR(1,1,1)
DISPLAY
SWAP_LIST
REG_PWM_DUTY – brightness, PWM_HZ, frequency
REG_GPIO – bit 7 = 1 – DISP
REG_PCLK = LCD dot/pixel clock frequency
CLEAR_COLOUR_RGB(0,0,0)
CLEAR(1,1,1)
** APPLICATION DATA **
DISPLAY
SWAP_LIST
Figure 3.1 Generic EVE Design Flow
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Application Note
AN_269 FT_App_Signature
Version 1.2
Document Reference No.: FT_000914 Clearance No.: FTDI# 364
3.1 Signature Flowchart
The flowchart below is specific to the Signature application.
Start
Set the Sketch
properties using
CMD_SKETCH
Clear the GRAM
Using
CMD_MEMZERO
Set the BITMAP
properties for Sketch
Read Tag by
using
REG_TOUCH_TAG
Clear?
YES
Clear GRAM
Bitmap
Data
NO
Animated
Background
LOOP
Draw Button for
Signature
Draw Clear Button with
TAG ‘C’
Display the constructed
displaylist
Figure 3.2 Flowchart
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Application Note
AN_269 FT_App_Signature
Version 1.2
Document Reference No.: FT_000914 Clearance No.: FTDI# 364
4 Description of the Functional Blocks
4.1 System Intialization
Configuration of the SPI master port is unique to each controller – different registers etc, but all
will require data to be sent Most Significant Bit (MSB) first with a little endian format.
The function labelled Ft_BootupConfig is generic to all applications and will start by toggling the
FT800 PD# pin to perform a power cycle.
/* Do a power cycle for safer side */
Ft_Gpu_Hal_Powercycle(phost,FT_TRUE);
Ft_Gpu_Hal_Rd16(phost,RAM_G);
/* Set the clk to external clock */
Ft_Gpu_HostCommand(phost,FT_GPU_EXTERNAL_OSC);
Ft_Gpu_Hal_Sleep(10);
/* Switch PLL output to 48MHz */
Ft_Gpu_HostCommand(phost,FT_GPU_PLL_48M);
Ft_Gpu_Hal_Sleep(10);
/* Do a core reset for safer side */
Ft_Gpu_HostCommand(phost,FT_GPU_CORE_RESET);
/* Access address 0 to wake up the FT800 */
Ft_Gpu_HostCommand(phost,FT_GPU_ACTIVE_M);
The internal PLL is then given a prompt by setting the clock register and PLL to 48 MHz.
Note 36MHz is possible but will have a knock on effect for the display timing parameters.
A software reset of the core is performed followed by a dummy read to address 0 to complete the
wake up sequence.
The FT800 GPIO lines are also controlled by writing to registers:
Ft_Gpu_Hal_Wr8(phost, REG_GPIO_DIR,0x80 | Ft_Gpu_Hal_Rd8(phost,REG_GPIO_DIR));
Ft_Gpu_Hal_Wr8(phost, REG_GPIO,0x080 | Ft_Gpu_Hal_Rd8(phost,REG_GPIO));
And these allow the display to be enabled.
To confirm the FT800 is awake and ready to start accepting display list information the identity
register is read in a loop until it reports back 0x7C. It will alsways be 0x7C if everything is awake
and functioning correctly.
ft_uint8_t chipid;
//Read Register ID to check if FT800 is ready.
chipid = Ft_Gpu_Hal_Rd8(phost, REG_ID);
while(chipid != 0x7C)
chipid = Ft_Gpu_Hal_Rd8(phost, REG_ID);
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Application Note
AN_269 FT_App_Signature
Version 1.2
Document Reference No.: FT_000914 Clearance No.: FTDI# 364
Once the FT800 is awake the display may be configured through 13 register writes according to its
resolution. Resolution and timing data should be available in the display datasheet.
Ft_Gpu_Hal_Wr16(phost, REG_HCYCLE, FT_DispHCycle);
Ft_Gpu_Hal_Wr16(phost, REG_HOFFSET, FT_DispHOffset);
Ft_Gpu_Hal_Wr16(phost, REG_HSYNC0, FT_DispHSync0);
Ft_Gpu_Hal_Wr16(phost, REG_HSYNC1, FT_DispHSync1);
Ft_Gpu_Hal_Wr16(phost, REG_VCYCLE, FT_DispVCycle);
Ft_Gpu_Hal_Wr16(phost, REG_VOFFSET, FT_DispVOffset);
Ft_Gpu_Hal_Wr16(phost, REG_VSYNC0, FT_DispVSync0);
Ft_Gpu_Hal_Wr16(phost, REG_VSYNC1, FT_DispVSync1);
Ft_Gpu_Hal_Wr8(phost, REG_SWIZZLE, FT_DispSwizzle);
Ft_Gpu_Hal_Wr8(phost, REG_PCLK_POL, FT_DispPCLKPol);
Ft_Gpu_Hal_Wr8(phost, REG_PCLK,FT_DispPCLK);//after this display is visible on the LCD
Ft_Gpu_Hal_Wr16(phost, REG_HSIZE, FT_DispWidth);
Ft_Gpu_Hal_Wr16(phost, REG_VSIZE, FT_DispHeight);
To complete the configuration the touch controller should also be calibrated
/* Touch configuration - configure the resistance value to 1200 - this value is specific to
customer requirement and derived by experiment */
Ft_Gpu_Hal_Wr16(phost, REG_TOUCH_RZTHRESH,1200);
Ft_Gpu_Hal_Wr8(phost, REG_GPIO_DIR,0xff);
Ft_Gpu_Hal_Wr8(phost, REG_GPIO,0x0ff);
An optional step is present in this code to clear the screen so that no artefacts from bootup are
displayed.
/*It is optional to clear the screen here*/
Ft_Gpu_Hal_WrMem(phost, RAM_DL,(ft_uint8_t *)FT_DLCODE_BOOTUP,sizeof(FT_DLCODE_BOOTUP));
Ft_Gpu_Hal_Wr8(phost, REG_DLSWAP,DLSWAP_FRAME);
4.2 Info()
This is a largely informational section of code and it starts by synchronising the physical xy
coordinates of the display’s touch layer with the display’s visual layer.
A display list is started and cleared:
Ft_Gpu_CoCmd_Dlstart(phost);
Ft_App_WrCoCmd_Buffer(phost,CLEAR(1,1,1));
Ft_App_WrCoCmd_Buffer(phost,COLOR_RGB(255,255,255));
A text instruction is printed on the display followed by the call to the internal calibrate function:
Ft_Gpu_CoCmd_Text(phost,FT_DispWidth/2,FT_DispHeight/2,26,OPT_CENTERX|OPT_CENTERY,"Please 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);
Next up in the Info() function is the FTDI logo playback:
Ft_Gpu_CoCmd_Logo(phost);
Ft_App_Flush_Co_Buffer(phost);
Ft_Gpu_Hal_WaitCmdfifo_empty(phost);
while(0!=Ft_Gpu_Hal_Rd16(phost,REG_CMD_READ));
dloffset = Ft_Gpu_Hal_Rd16(phost,REG_CMD_DL);
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Application Note
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Version 1.2
Document Reference No.: FT_000914 Clearance No.: FTDI# 364
dloffset -=4;
Ft_Gpu_Hal_WrCmd32(phost,CMD_MEMCPY);
Ft_Gpu_Hal_WrCmd32(phost,100000L);
Ft_Gpu_Hal_WrCmd32(phost,RAM_DL);
Ft_Gpu_Hal_WrCmd32(phost,dloffset);
play_setup();
A composite image with the logo and a start arrow is then displayed to allow the user to start the
main application
do
{
Ft_Gpu_CoCmd_Dlstart(phost);
Ft_Gpu_CoCmd_Append(phost,100000L,dloffset);
Ft_App_WrCoCmd_Buffer(phost,BITMAP_TRANSFORM_A(256));
Ft_App_WrCoCmd_Buffer(phost,BITMAP_TRANSFORM_A(256));
Ft_App_WrCoCmd_Buffer(phost,BITMAP_TRANSFORM_B(0));
Ft_App_WrCoCmd_Buffer(phost,BITMAP_TRANSFORM_C(0));
Ft_App_WrCoCmd_Buffer(phost,BITMAP_TRANSFORM_D(0));
Ft_App_WrCoCmd_Buffer(phost,BITMAP_TRANSFORM_E(256));
Ft_App_WrCoCmd_Buffer(phost,BITMAP_TRANSFORM_F(0));
Ft_App_WrCoCmd_Buffer(phost,SAVE_CONTEXT());
Ft_App_WrCoCmd_Buffer(phost,COLOR_RGB(219,180,150));
Ft_App_WrCoCmd_Buffer(phost,COLOR_A(220));
Ft_App_WrCoCmd_Buffer(phost,BEGIN(EDGE_STRIP_A));
Ft_App_WrCoCmd_Buffer(phost,VERTEX2F(0,FT_DispHeight*16));
Ft_App_WrCoCmd_Buffer(phost,VERTEX2F(FT_DispWidth*16,FT_DispHeight*16));
Ft_App_WrCoCmd_Buffer(phost,COLOR_A(255));
Ft_App_WrCoCmd_Buffer(phost,RESTORE_CONTEXT());
Ft_App_WrCoCmd_Buffer(phost,COLOR_RGB(0,0,0));
// INFORMATION
Ft_Gpu_CoCmd_Text(phost,FT_DispWidth/2,20,28,OPT_CENTERX|OPT_CENTERY,info[0]);
Ft_Gpu_CoCmd_Text(phost,FT_DispWidth/2,60,26,OPT_CENTERX|OPT_CENTERY,info[1]);
Ft_Gpu_CoCmd_Text(phost,FT_DispWidth/2,90,26,OPT_CENTERX|OPT_CENTERY,info[2]);
Ft_Gpu_CoCmd_Text(phost,FT_DispWidth/2,120,26,OPT_CENTERX|OPT_CENTERY,info[3]);
Ft_Gpu_CoCmd_Text(phost,FT_DispWidth/2,FT_DispHeight-30,26,OPT_CENTERX|OPT_CENTERY,"Click
to play");
if(sk!='P')
Ft_App_WrCoCmd_Buffer(phost,COLOR_RGB(255,255,255));
else
Ft_App_WrCoCmd_Buffer(phost,COLOR_RGB(100,100,100));
Ft_App_WrCoCmd_Buffer(phost,BEGIN(FTPOINTS));
Ft_App_WrCoCmd_Buffer(phost,POINT_SIZE(20*16));
Ft_App_WrCoCmd_Buffer(phost,TAG('P'));
Ft_App_WrCoCmd_Buffer(phost,VERTEX2F((FT_DispWidth/2)*16,(FT_DispHeight-60)*16));
Ft_App_WrCoCmd_Buffer(phost,COLOR_RGB(180,35,35));
Ft_App_WrCoCmd_Buffer(phost,BEGIN(BITMAPS));
Ft_App_WrCoCmd_Buffer(phost,VERTEX2II((FT_DispWidth/2)-14,(FT_DispHeight-75),14,0));
Ft_App_WrCoCmd_Buffer(phost,DISPLAY());
Ft_Gpu_CoCmd_Swap(phost);
Ft_App_Flush_Co_Buffer(phost);
Ft_Gpu_Hal_WaitCmdfifo_empty(phost);
}while(Read_Keys()!='P');
4.3 Home_setup()
The background star image that is rotated in the background is located in line with the code. It is
actually compressed data at the MCU or PC:
static ft_uint8_t home_star_icon[] = {0x78,0x9C,0xE5,0x94,0xBF,0x4E,0xC2,0x40,0x1C…
The home_setup function is run once prior to displaying the FTDI logo through Info(). It takes this
data and decompresses it as it’s stored in the GRAM:
Ft_Gpu_Hal_WrCmd32(phost,CMD_INFLATE);
Ft_Gpu_Hal_WrCmd32(phost,250*1024L);
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Application Note
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Version 1.2
Document Reference No.: FT_000914 Clearance No.: FTDI# 364
Ft_Gpu_Hal_WrCmdBuf(phost,home_star_icon,sizeof(home_star_icon));
The initial display list is started by clearing the buffers and setting main colour set to white:
Ft_Gpu_CoCmd_Dlstart(phost);
// start
Ft_App_WrCoCmd_Buffer(phost,CLEAR(1,1,1));
Ft_App_WrCoCmd_Buffer(phost,COLOR_RGB(255, 255, 255));
The data for the star which was loaded with CMD_INFLATE is now assigned two handles so the
images can be displayed and manipulated:
Ft_App_WrCoCmd_Buffer(phost,BITMAP_HANDLE(13));
// handle for background stars
Ft_App_WrCoCmd_Buffer(phost,BITMAP_SOURCE(250*1024L));
// Starting address in gram
Ft_App_WrCoCmd_Buffer(phost,BITMAP_LAYOUT(L4, 16, 32)); // format
Ft_App_WrCoCmd_Buffer(phost,BITMAP_SIZE(NEAREST, REPEAT, REPEAT, 512, 512 ));
Ft_App_WrCoCmd_Buffer(phost,BITMAP_HANDLE(14));
// handle for background stars
Ft_App_WrCoCmd_Buffer(phost,BITMAP_SOURCE(250*1024L));
// Starting address in gram
Ft_App_WrCoCmd_Buffer(phost,BITMAP_LAYOUT(L4, 16, 32)); // format
Ft_App_WrCoCmd_Buffer(phost,BITMAP_SIZE(NEAREST, BORDER, BORDER, 32, 32 ));
Ft_App_WrCoCmd_Buffer(phost,DISPLAY());
The cleared display is now shown. While nothing is actually drawn on the screen with this display
list, the stars are now in place for later use:
Ft_Gpu_CoCmd_Swap(phost);
Ft_App_Flush_Co_Buffer(phost);
Ft_Gpu_Hal_WaitCmdfifo_empty(phost);
4.4 Signature()
The Signature function starts by calculating the size of the signature area based on the screen
size:
ft_uint16_t w,h,x,y,tag;
ft_int16_t sw
ft_int16_t sh
ft_int16_t ox
ft_int16_t oy
ft_uint16_t a
x
y
w
h
=
=
=
=
=
2 * FT_DispWidth / 3;
sw / 3;
( FT_DispWidth - sw) / 2;
(2 * FT_DispHeight / 3) - sh;
0;
= FT_DispWidth*0.168;
= FT_DispHeight*0.317;
= FT_DispWidth-(2*x);
= FT_DispHeight-(2*y);
The display list is started and buffers cleared.
Ft_Gpu_CoCmd_Dlstart(phost);
// start
Ft_App_WrCoCmd_Buffer(phost,CLEAR(1,1,1));
Then it clears the GRAM memory covering the size of the display with CMD_MEMZERO, followed by
drawing the signature area:
Ft_Gpu_CoCmd_MemZero(phost,10*1024L,480L*272L); // Clear the gram from 1024
Ft_Gpu_CoCmd_Sketch(phost,x,y,w,h,10*1024L,L8);
At this point, the signature area is just that – there is nothing drawn on the screen to indicate the
boundaries. That’s done a bit later in the display list. The CMD_SKETCH command continually
translates the X-Y touch coordinates within the sketch area and changes those locations in the
GRAM from the foreground colour to background colour. By doing this, the image of the signature
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Document Reference No.: FT_000914 Clearance No.: FTDI# 364
is shown on the screen. Once complete, the GRAM corresponding to the sketch area can be read
by the MCU and stored as a signature image. This example does not store any sketch data.
After enabling the signature area, the cleared memory is displayed to ensure a blank screen with
no artifacts. The display list is swapped to become active and any remaining command buffer is
flushed:
Ft_App_WrCoCmd_Buffer(phost,BITMAP_HANDLE(1));
// handle for background stars
Ft_App_WrCoCmd_Buffer(phost,BITMAP_SOURCE(10*1024L));
Ft_App_WrCoCmd_Buffer(phost,BITMAP_LAYOUT(L8,w,h));
Ft_App_WrCoCmd_Buffer(phost,BITMAP_SIZE(NEAREST,BORDER,BORDER,w,h));
Ft_Gpu_CoCmd_Swap(phost);
Ft_App_Flush_Co_Buffer(phost);
Ft_Gpu_Hal_WaitCmdfifo_empty(phost);
With the visible display initialization complete, the screen elements can now be drawn. A while()
loop will create a new display list each time through. The display list will contain the moving stars
and display any activity on the touch screen for both the signature area and clear button.
The clear button is assigned a touch tag. Tags remove the need correspond the X-Y touch
coordinates with a drawn element. Instead, the entire element is assigned a tag number. The
FT800 determines whether the touch event was inside the element boundaries then assigns the
appropriate tag. This frees up considerable host MCU time.
The first item in the while() loop is to see if there are any touch events and whether a tag is
assigned. If the CLEAR button is tapped, the signature area is cleared by resetting the GRAM to
the original zero values:
tag = Ft_Gpu_Hal_Rd8(phost,REG_TOUCH_TAG);
if(tag=='O')
{
Ft_Gpu_CoCmd_Dlstart(phost);
Ft_Gpu_CoCmd_MemZero(phost,10*1024L,480L*272L); // Clear the gram from 1024
Ft_App_Flush_Co_Buffer(phost);
Ft_Gpu_Hal_WaitCmdfifo_empty(phost);
}
The display list is started and buffers flushed:
Ft_Gpu_CoCmd_Dlstart(phost);
// start
Ft_App_WrCoCmd_Buffer(phost, CLEAR(1,1,1));
Next, the background stars are drawn. This is done by repeating a single star image over the
entire screen (actually double the size of the screen – as if a large sheet of printed stars were laid
over the screen extending beyond the edges). This is repeated a total of three times – one each
for red, green and blue coloured stars. The three layers of stars are made semi-transparent and
blended to allow all of the items to be seen even if they’re on top of each other. Each time
through the while() loop, the three layers are rotated to give the appearance of spinning sheets of
stars. In addition to the spinning layers, the star images themselves are rotated.
The display context is saved and restored, similar to a microcontroller stack push and pop. This
allows the foreground image to remain static while the background images are changed:
Ft_App_WrCoCmd_Buffer(phost,SAVE_CONTEXT());
Ft_App_WrCoCmd_Buffer(phost,BLEND_FUNC(SRC_ALPHA, ONE));
Ft_App_WrCoCmd_Buffer(phost,COLOR_RGB(78, 0, 0));
Ft_App_WrCoCmd_Buffer(phost,CMD_LOADIDENTITY);
rotate_around(ox, oy, 47*a);
Ft_App_WrCoCmd_Buffer(phost,VERTEX2II(0, 0, 13, 1));
Ft_App_WrCoCmd_Buffer(phost,COLOR_RGB(0, 40, 0));
rotate_around(ox + sw, oy, 53*a);
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Document Reference No.: FT_000914 Clearance No.: FTDI# 364
Ft_App_WrCoCmd_Buffer(phost,VERTEX2II(0, 0, 13, 1));
Ft_App_WrCoCmd_Buffer(phost,COLOR_RGB(0, 0, 78));
rotate_around(ox, oy + sh, 57*a);
Ft_App_WrCoCmd_Buffer(phost,VERTEX2II(0, 0, 13, 1));
Ft_App_WrCoCmd_Buffer(phost,RESTORE_CONTEXT());
After displaying the new star layers and returning to the foreground, the signature area and CLEAR
button are displayed. The CLEAR button is assigned a tag of ‘0’, which is checked at the beginning
of the while() loop.
Ft_Gpu_CoCmd_FgColor(phost,0xffffff);
// Set the fg color
Ft_Gpu_CoCmd_Button(phost,x,y,w,h,31,OPT_FLAT,"");
Ft_App_WrCoCmd_Buffer(phost,COLOR_RGB(0,0,0));
Ft_App_WrCoCmd_Buffer(phost,BEGIN(BITMAPS));
Ft_App_WrCoCmd_Buffer(phost,VERTEX2II(x,y,1,0));
if(tag=='O')
Ft_Gpu_CoCmd_FgColor(phost,0x003300);
else
Ft_Gpu_CoCmd_FgColor(phost,0x005500);
Ft_App_WrCoCmd_Buffer(phost,COLOR_RGB(255, 255, 255));
Ft_App_WrCoCmd_Buffer(phost,TAG('O'));
Ft_Gpu_CoCmd_Button(phost,FT_DispWidth / 2 - sw / 4, FT_DispHeight - sh / 2 - 3, sw / 2, sh /
2, 28, 0, "CLEAR");
The final section of the while() loop is to swap the display list to make it active, flush the buffers
and return to the top of the loop. The variable ‘a’ is used for the star layer rotation angle in the
next pass:
Ft_App_WrCoCmd_Buffer(phost,DISPLAY());
Ft_Gpu_CoCmd_Swap(phost);
Ft_App_Flush_Co_Buffer(phost);
Ft_Gpu_Hal_WaitCmdfifo_empty(phost);
a+=1;
4.4.1 FT801 Signature
The FT801 capacitive display uses a different (capacitive) display touch controller compared to the
FT800 resistive controller which has a slower sample rate than the resistive display. To ensure
smooth interaction between the user touch and the application, CMD_SKETCH is replaced with
CMD_CSKETCH. To enable this alternative command in the sample program open the Platform.h
file and look for:
#define FT_801_ENABLE
By default this is undefined (FT800 mode). To switch in the CMD_CSKETCH ensure this line is
defined. After making the change, rebuild and run the application.
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5 Operation of the Application
This application demonstrates the usage of graphics primitives such as bitmaps and inbuilt
signature function, text & button widgets.
The application constantly tracks the user touch on the signature area by using sketch function
and monitors the user tap on the clear button to clear the signature drawn by the user. The
application displays animated star bitmaps in three layers with different colours on the
background. These three layers of star bitmaps are rotated with respective to centre axis and
rotary rate. The sketch area can be cleared using clear button.
Figure 5.1 Signature Display
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6 Contact Information
Head Office – Glasgow, UK
Branch Office – Tigard, Oregon, USA
Future Technology Devices International Limited
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Branch Office – Shanghai, China
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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
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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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Appendix A– References
6.1 Document References
1.
2.
3.
4.
5.
FT800 datasheet
FT801 datasheet
Programming Guide covering EVE command language
AN_240 FT800 From the Ground Up
AN_245 VM800CB_SampleApp_PC_Introduction - covering detailed design flow with a PC
and USB to SPI bridge cable
6. AN_246 VM800CB_SampleApp_Arduino_Introduction – covering detailed design flow in an
Arduino platform
7. VM800C datasheet
8. VM800B datasheet
6.2 Acronyms and Abbreviations
Terms
Description
Arduino Pro
The open source platform variety based on ATMEL’s ATMEGA chipset
EVE
Embedded Video Engine
SPI
Serial Peripheral Interface
UI
User Interface
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Appendix B – List of Tables & Figures
6.3 List of Figures
Figure 3.1 Generic EVE Design Flow ........................................................................... 5
Figure 3.2 Flowchart .................................................................................................. 6
Figure 4.1 Signature Display .................................................................................... 13
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Version 1.2
Document Reference No.: FT_000914 Clearance No.: FTDI# 364
Appendix C– Revision History
Document Title:
AN_269 FT_App_Signature
Document Reference No.:
FT_000914
Clearance No.:
FTDI# 364
Product Page:
http://www.ftdichip.com/EVE.htm
Document Feedback:
Send Feedback
Revision
Changes
Date
0.1
Initial draft release
2013-07-18
1.0
Version 1.0 updated wrt review comments
2013-08-21
1.1
Included code discussion
2013-10-08
1.1
Version 1.1
2013-11-01
1.2
Added section 4.4.1
2014-06-30
17
Copyright © 2014 Future Technology Devices International Limited