Silicon Labs
Display driver for Sharp's range of SPI-driven memory LCD's, leveraging the power of asynchronous transfers. Currently supports LS013B7DH03, but easily extendable to other models as well.
Dependents: memLCD-Demo memLCD-Demo memLCD-Demo MemLCD-Temperature-Humidity-Demo ... more
Information
All examples in this repo are considered EXPERIMENTAL QUALITY, meaning this code has been created as one-off proof-of-concept and is suitable as a demonstration for experimental purposes only. This code will not be regularly maintained by Silicon Labs and there is no guarantee that these projects will work across all environments, SDK versions and hardware.
Caution
This library builds upon the asynchronous SPI interface provided by mbed, but not all platforms currently support this. So, make sure your platform is capable of asynchronous SPI (all Silicon Labs platforms are), otherwise you will get compiler errors!
Usage
The library is purposefully quite simple to use. To set it up, you initialize an SPI object and the required I/O pins, and call the library constructor with those. Make sure the display is powered on, enabled, and the inversion mode is set to external (EXTMODE is high).
setup
#define SCK PD2 #define MOSI PD0 DigitalOut CS(PD3); DigitalOut EXTCOM(PC4); SPI displaySPI(MOSI, NC, SCK); silabs::LS013B7DH03 display(&displaySPI, &CS, &EXTCOM);
You should also swap out the pin names for the relevant names on your platform.
After setup, you usually want to clear any static information left on the screen. To do that, you would call clearImmediate, and optionally provide a callback. The callback will get called when the clearing operation is complete and the display has been cleared. In this example, refreshCallback sets a global boolean 'refreshed' to true when called.
clearing the display
refreshed = false;
int result = display.clearImmediate(refreshCallback);
if(result == LS013B7DH03_OK) {
while(refreshed == false) sleep();
} else {
printf("Display error: %d", result);
}
Of course, instead of sleeping while the display is clearing, you could also just continue with the program, and check back whether the callback happened or not.
Then comes the fun part, actually writing stuff on the display! Since the display only supports one-way communication (i.e. you cannot read from it), it uses an internal frame buffer in RAM. So, to actually display something on the LCD, two steps need to happen: writing to the pixel buffer, and at the very end writing the pixel buffer to the LCD.
Pixelbuffer operations
The MemoryLCD library builds upon Simon Ford's TextDisplay library, which means you can use all of that functionality. Even printf is supported!
most important display operations
// Set one pixel at x=10, y=40 to the color White
display.pixel(10,40,White);
// print "I love mbed" at the character position x=4, y=5
// i.e. starting on row 5, 4 characters from the left border
display.locate(4,5);
display.printf("I love mbed!");
// show a bitmap at a given location
// Constraints: bitmap is 8-bit, MSB first, 1 bit per pixel. Width, height and starting coordinates must be divisible by 8.
// This example: show a bitmap which is 128 pixels wide and high, and start at location 0,0.
display.showBMP(&mbed_logo, 128, 128, 0, 0);
//Draw a line (really a 1px wide rectangle) from (4,10) until (4,15)
display.fill(4, 10, 1, 5, White);
Updating the LCD
Updating the LCD (i.e. moving the framebuffer to the display) happens much the same way as clearing it: asynchronously. To start the update, you call update() on the display, optionally providing a callback to be called after the whole update has happened. In the example below, refreshCallback sets a global boolean 'refreshed' to true when called. Signature: void refreshCallback(void);
updating the display
refreshed = false;
int result = display.update(refreshCallback);
if(result == LS013B7DH03_OK) {
while(refreshed == false) sleep();
} else {
printf("Display error: %d", result);
}
Full example
example program
#include "LS013B7DH03.h"
#include "mbed_logo.h"
/******************** Define I/O *****************************/
DigitalOut myled(LED1);
#define SCK PD2
#define MOSI PD0
DigitalOut CS(PD3);
DigitalOut EXTCOM(PC4);
DigitalOut EXTMODE(PD4);
DigitalOut DISP(PD5);
SPI displaySPI(MOSI, NC, SCK);
silabs::LS013B7DH03 display(&displaySPI, &CS, &EXTCOM);
/******************** Define Timers *****************************/
LowPowerTicker timeKeeping;
/***************** Define global variables **********************/
#define INIT_SECONDS 17600
volatile uint32_t prevSeconds = INIT_SECONDS, seconds = INIT_SECONDS;
volatile bool refreshed = false;
/***************** Define callback handlers *********************/
void secondsCallback(void);
void refreshCallback(void);
void secondsCallback(void) {
seconds++;
}
/**
* Callback for refresh completion
*/
void refreshCallback(void) {
refreshed = true;
}
/*************************** MAIN *******************************/
int main() {
// Enable the LCD
EXTMODE = 1;
DISP = 1;
// Start generating the 1Hz call for keeping time
timeKeeping.attach(&secondsCallback, 1.0f);
// Reset the LCD to a blank state. (All white)
refreshed = false;
display.clearImmediate(refreshCallback);
while(refreshed == false) sleep();
printf("Initialization done! \n");
// Apply mbed logo bitmap to the pixel buffer
display.showBMP((uint8_t*)mbed_enabled_logo, 128, 128, 0, 0);
display.printf("I like MBED!");
// Push update to the display
refreshed = false;
display.update(refreshCallback);
// Sleep while doing the transmit
while(refreshed == false) sleep();
// Go into clock mode
while(1) {
sleep();
// In clock mode, only update once per second
if(prevSeconds != seconds) {
display.locate(4,15);
display.printf("%02d:%02d:%02d", (seconds / 1200) % 24, (seconds / 60) % 60, seconds % 60);
if(refreshed == true) {
prevSeconds = seconds;
refreshed = false;
display.update(refreshCallback);
}
}
}
}
Datasheet
Datasheet for the LCD (hosted by Mouser)
BufferedDisplay.h
- Committer:
- stevew817
- Date:
- 2015-08-12
- Revision:
- 11:0f8ae10b308d
- Parent:
- 6:fe04073fe90c
File content as of revision 11:0f8ae10b308d:
/***************************************************************************//**
* @file BufferedDisplay.h
* @brief Framebuffered version of GraphicsDisplay
*******************************************************************************
* @section License
* <b>(C) Copyright 2015 Silicon Labs, http://www.silabs.com</b>
*******************************************************************************
*
* Permission is granted to anyone to use this software for any purpose,
* including commercial applications, and to alter it and redistribute it
* freely, subject to the following restrictions:
*
* 1. The origin of this software must not be misrepresented; you must not
* claim that you wrote the original software.
* 2. Altered source versions must be plainly marked as such, and must not be
* misrepresented as being the original software.
* 3. This notice may not be removed or altered from any source distribution.
*
* DISCLAIMER OF WARRANTY/LIMITATION OF REMEDIES: Silicon Labs has no
* obligation to support this Software. Silicon Labs is providing the
* Software "AS IS", with no express or implied warranties of any kind,
* including, but not limited to, any implied warranties of merchantability
* or fitness for any particular purpose or warranties against infringement
* of any proprietary rights of a third party.
*
* Silicon Labs will not be liable for any consequential, incidental, or
* special damages, or any other relief, or for any claim by any third party,
* arising from your use of this Software.
*
******************************************************************************/
#ifndef SILABS_BUFFEREDDISPLAY_H
#define SILABS_BUFFEREDDISPLAY_H
#include "GraphicsDisplay.h"
#include "LCDSettings.h"
namespace silabs {
/** Framebuffered version of GraphicsDisplay
*
* This has been implemented as part of the MemoryLCD library.
*/
class BufferedDisplay : public GraphicsDisplay {
public:
BufferedDisplay(const char *name=NULL);
/**
* Override of GraphicsDisplay pixel() function to set a pixel in the buffer
*
* @param x Zero-based x-axis index of pixel to set. 0 = leftmost.
* @param y Zero-based y-axis index of pixel to set. 0 = topmost.
* @param colour Colour value to set pixel to. In this implementation, only LSB is taken into account.
*/
virtual void pixel(int x, int y, int colour);
virtual int width();
virtual int height();
/**
* Function to move bitmap into frame buffer
*
* @param bitmap pointer to uint8 array containing horizontal pixel data
* @param bmpWidth width of the bitmap in pixels (must be multiple of 8)
* @param bmpHeight height of the bitmap in pixels
* @param startX starting position to apply bitmap in horizontal direction (0 = leftmost) (must be multiple of 8)
* @param startY starting position to apply bitmap in vertical direction (0 = topmost)
*/
void showBMP(const uint8_t* bitmap, const uint32_t bmpWidth, const uint32_t bmpHeight, const uint32_t startX, const uint32_t startY);
protected:
volatile DISPLAY_BUFFER_TYPE _pixelBuffer[DISPLAY_BUFFER_ELEMENTS]; // one full frame buffer
volatile DISPLAY_BUFFER_TYPE _dirtyRows[DISPLAY_HEIGHT/DISPLAY_BUFFER_TYPE_SIZE]; // 1 bit per row to indicate dirty status
};
} // namespace silabs
#endif //SILABS_BUFFEREDDISPLAY_H
