Difference between revisions of "STM32F107VC/Using MCBQVGA-TS-Display-v12"
From Teknologisk videncenter
m (→Keil MCBSTM32C board) |
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===Example code=== | ===Example code=== | ||
Still experimental and missing documentation | Still experimental and missing documentation | ||
| − | ;Note:To change Pulse Width change the value of '''TIM3-> | + | ;Note:To change Pulse Width change the value of '''TIM3->CCR3''' |
<source lang=c> | <source lang=c> | ||
| + | /* | ||
| + | Example 2: | ||
| + | ========== | ||
| + | Using timer 3 to Dim the Backlight in Display | ||
| + | |||
| + | Mode : Continues PWM mode to PB0. Section 15.3.9 page 370 | ||
| + | For details see: http://mars.tekkom.dk/mediawiki/index.php/STM32F107VC/Using_MCBQVGA-TS-Display-v12 | ||
| + | */ | ||
void tim3init( void ) { | void tim3init( void ) { | ||
| − | + | GPIOB->CRL |= 0xa; // Set PB0 as Alternate function Push-Pull | |
| − | GPIOB->CRL |= 0xa; | + | RCC->APB1ENR |= 2; //Enable timer 3 clock (RCC->APB1ENR bit 1 = 1) |
| − | |||
| − | |||
| − | |||
| − | |||
| − | + | ||
| − | + | TIM3->PSC = 72; // Prescaler: With timer 3 input clock 72 Mhz divide by 72 to 1 Mhz | |
| − | TIM3->PSC = 72; | + | TIM3->ARR = 1000; // Auto Reload Register set to 1000 divide 1Mhz/1000 = 1 Khz |
| − | TIM3->ARR = 1000; | + | TIM3->CCR3 = 100; //Compare Regisger for channel 3 |
| − | TIM3->CCR3 = 100; | ||
TIM3->CCMR2 |= 7 << 4; //PWM mode 1 | TIM3->CCMR2 |= 7 << 4; //PWM mode 1 | ||
TIM3->CCMR2 |= 1 << 3; | TIM3->CCMR2 |= 1 << 3; | ||
| Line 30: | Line 33: | ||
TIM3->CCER |= 1<<8; //Polarity | TIM3->CCER |= 1<<8; //Polarity | ||
TIM3->CCER |= 1<<9; | TIM3->CCER |= 1<<9; | ||
| − | |||
| − | |||
| − | |||
| − | |||
// Step 3: Enable Counter (TIM3_CR1 bit 0 = 1) | // Step 3: Enable Counter (TIM3_CR1 bit 0 = 1) | ||
TIM3->CR1 |= 1; | TIM3->CR1 |= 1; | ||
| + | } | ||
| + | |||
| + | /* Change Display Backlight Intensity | ||
| + | input: 0 - 17 ( 0 = 0% backlight 17 = 100% backlight | ||
| + | Cavets: No errorcontrol | ||
| + | */ | ||
| + | void backlight( int intensity ) { | ||
| + | int disvalarr[] = {0,5,10,15,25,35,50,65,80,100,120,150,200,300,400,600,800,1000}; | ||
| + | TIM3->CCR3 = disvalarr[intensity]; | ||
} | } | ||
</source> | </source> | ||
Revision as of 08:57, 20 January 2012
Contents
Backlight illumination adjust
The signal BL_control[1] turns on the Backlight LED's controlled by the STLD40D[2] IC on the display. To control the illuminace of the LED's its necessary to turn the LED's off and on using Pulse-Width-Modulation (PWM).
Keil MCBSTM32C board
On the Keil MCBSTM32C board the BL_control signal is connected to PB0 (Port B bit 0).
- Looking in the Reference Maual on page 173 section 9.3.7 table 44 it's seen that Timer 3 Channel 3 has an alternate function on PB0.
- To see Timer 3's possibilities on PB0 look on page 161 section 9.1.11 table 23 it's seen that timer 3 can use a GPIO pin as Output Compare Channel X when the pin is configured as Alternate Function Push-Pull.
- To set PB0 as Alternate Function Push-Pull - See the GPIOx_CRL register on page 166.
- To configure Timer 3 as continues PWM output timer see Page 371 section 15.3.9
Example code
Still experimental and missing documentation
- Note
- To change Pulse Width change the value of TIM3->CCR3
/*
Example 2:
==========
Using timer 3 to Dim the Backlight in Display
Mode : Continues PWM mode to PB0. Section 15.3.9 page 370
For details see: http://mars.tekkom.dk/mediawiki/index.php/STM32F107VC/Using_MCBQVGA-TS-Display-v12
*/
void tim3init( void ) {
GPIOB->CRL |= 0xa; // Set PB0 as Alternate function Push-Pull
RCC->APB1ENR |= 2; //Enable timer 3 clock (RCC->APB1ENR bit 1 = 1)
TIM3->PSC = 72; // Prescaler: With timer 3 input clock 72 Mhz divide by 72 to 1 Mhz
TIM3->ARR = 1000; // Auto Reload Register set to 1000 divide 1Mhz/1000 = 1 Khz
TIM3->CCR3 = 100; //Compare Regisger for channel 3
TIM3->CCMR2 |= 7 << 4; //PWM mode 1
TIM3->CCMR2 |= 1 << 3;
TIM3->EGR |= 1;
TIM3->CCER |= 1<<8; //Polarity
TIM3->CCER |= 1<<9;
// Step 3: Enable Counter (TIM3_CR1 bit 0 = 1)
TIM3->CR1 |= 1;
}
/* Change Display Backlight Intensity
input: 0 - 17 ( 0 = 0% backlight 17 = 100% backlight
Cavets: No errorcontrol
*/
void backlight( int intensity ) {
int disvalarr[] = {0,5,10,15,25,35,50,65,80,100,120,150,200,300,400,600,800,1000};
TIM3->CCR3 = disvalarr[intensity];
}
Links
- MCBSTM32C Display Schematics (Loads PDF)
- AM-240320LDTNQW TFT-LCD Display module with Touch Panel (Loads PDF)
- SPFD5408B 720 channel driver for TFT-LCD Display (Loads PDF)
- STMPE811 Touch Screen Controller
- STLD40D White LED power supply for large display backlight (Loads PDF)