Adding 16-bit brightness control to LCD backlight

diff --git a/Scan/STLcd/capabilities.kll b/Scan/STLcd/capabilities.kll
new file mode 100644 (file)
index 0000000..a327bc2
--- /dev/null
+++ b/Scan/STLcd/capabilities.kll
@@ -0,0 +1,44 @@
+Name = STLcdCapabilities;
+Version = 0.1;
+Author = "HaaTa (Jacob Alexander) 2015";
+KLL = 0.3c;
+
+# Modified Date
+Date = 2015-08-01;
+
+# Defines available to the STLcd sub-module
+
+# PWM Prescalar
+# In general this can be left alone
+# A higher prescalar should be lower power usage (less switching)
+# However, flickering may be noticeable.
+#
+# Here's a calculation table valid at a 72 MHz system clock
+# Prescalars range from 0 to 7 (1 to 128)
+# 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
+# Defaulting to no prescalar, looks the best
+STLcdBacklightPrescalar => STLcdBacklightPrescalar_define;
+STLcdBacklightPrescalar = 0;
+
+# Default Backlight Channel Brightness
+# There are 3 channels, RGB
+# In order to get other colors you must mix the 3 colors
+# Each channel is a 16-bit register (65536 levels)
+# Technically, this means, the backlight is a 48-bit RGB pixel
+# In practice, it may be difficult to get color consistency at times if too bright or too dim
+STLcdBacklightRed   => STLcdBacklightRed_define;
+STLcdBacklightGreen => STLcdBacklightGreen_define;
+STLcdBacklightBlue  => STLcdBacklightBlue_define;
+
+# Defaults to 6% brightness, white
+STLcdBacklightRed   = 0xFFF;
+STLcdBacklightGreen = 0xFFF;
+STLcdBacklightBlue  = 0xFFF;
+

diff --git a/Scan/STLcd/lcd_scan.c b/Scan/STLcd/lcd_scan.c
index df07b5aa9391209772458851f3a8dc41dc6792dc..49a1b82e6f6ed547c0e3d2f66085d2f18c06c29a 100644 (file)
--- a/Scan/STLcd/lcd_scan.c
+++ b/Scan/STLcd/lcd_scan.c
@@ -21,6 +21,7 @@
 
 // Project Includes
 #include <cli.h>
 
 // Project Includes
 #include <cli.h>

+#include <kll.h>

 #include <led.h>
 #include <print.h>
 
 #include <led.h>
 #include <print.h>
 


@@ -276,16 +277,49 @@ inline void LCD_setup()
 
        // Setup Backlight
        // TODO Expose default settings
 
        // 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);

 }
 
 
 }