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Adding 16-bit brightness control to LCD backlight

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This commit is contained in:
Jacob Alexander 2015-08-01 21:59:43 -07:00
parent 581b464a13
commit 64b232c878
2 changed files with 88 additions and 10 deletions
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54
Scan/STLcd/lcd_scan.c
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@ -21,6 +21,7 @@
// Project Includes
#include <cli.h>
#include <kll.h>
#include <led.h>
#include <print.h>
@ -276,16 +277,49 @@ inline void LCD_setup()
// Setup Backlight
// TODO Expose default settings
// TODO Setup PWM
GPIOC_PDDR |= (1<<1);
PORTC_PCR1 = PORT_PCR_SRE | PORT_PCR_DSE | PORT_PCR_MUX(1);
GPIOC_PCOR |= (1<<1);
GPIOC_PDDR |= (1<<2);
PORTC_PCR2 = PORT_PCR_SRE | PORT_PCR_DSE | PORT_PCR_MUX(1);
GPIOC_PCOR |= (1<<2);
GPIOC_PDDR |= (1<<3);
PORTC_PCR3 = PORT_PCR_SRE | PORT_PCR_DSE | PORT_PCR_MUX(1);
GPIOC_PCOR |= (1<<3);
SIM_SCGC6 |= SIM_SCGC6_FTM0;
FTM0_CNT = 0; // Reset counter
// PWM Period
// 16-bit maximum
FTM0_MOD = 0xFFFF;
// Set FTM to PWM output - Edge Aligned, Low-true pulses
FTM0_C0SC = 0x24; // MSnB:MSnA = 10, ELSnB:ELSnA = 01
FTM0_C1SC = 0x24;
FTM0_C2SC = 0x24;
// Base FTM clock selection (72 MHz system clock)
// Pre-scalar calculations
// 0 - 72 MHz - Highest power usage/best result
// 1 - 36 MHz
// 2 - 18 MHz
// 3 - 9 MHz - Slightly visible flicker (peripheral vision)
// 4 - 4 500 kHz - Visible flickering
// 5 - 2 250 kHz
// 6 - 1 125 kHz
// 7 - 562 500 Hz
// System clock, /w prescalar setting
FTM0_SC = FTM_SC_CLKS(1) | FTM_SC_PS( STLcdBacklightPrescalar_define );
/* Write frequency TODO API
FTM0_SC = 0;
FTM0_CNT = 0;
FTM0_MOD = mod;
FTM0_SC = FTM_SC_CLKS(1) | FTM_SC_PS(prescale);
*/
// Red
FTM0_C0V = STLcdBacklightRed_define;
PORTC_PCR1 = PORT_PCR_SRE | PORT_PCR_DSE | PORT_PCR_MUX(4);
// Green
FTM0_C1V = STLcdBacklightGreen_define;
PORTC_PCR2 = PORT_PCR_SRE | PORT_PCR_DSE | PORT_PCR_MUX(4);
// Blue
FTM0_C2V = STLcdBacklightBlue_define;
PORTC_PCR3 = PORT_PCR_SRE | PORT_PCR_DSE | PORT_PCR_MUX(4);
}