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Meizu: update backlight brightness curve so backlight is still on at the minimum brightness setting

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@22102 a1c6a512-1295-4272-9138-f99709370657
This commit is contained in:
Bertrik Sikken 2009-08-01 18:28:25 +00:00
parent fc570147e6
commit 1b2fe50f3d

View file

@ -34,29 +34,30 @@
void _backlight_set_brightness(int brightness) void _backlight_set_brightness(int brightness)
{ {
/* pwm = (sqrt(2)**x)-1, where brightness level x = 0..16 */ /* pwm = round(sqrt(2)**x), where brightness level x = 1..16 */
static const unsigned char logtable[] = static const unsigned int logtable[] =
{0, 1, 2, 3, 5, 7, 10, 15, 22, 31, 44, 63, 90, 127, 180, 255}; {1, 2, 3, 4, 6, 8, 11, 16, 23, 32, 45, 64, 91, 128, 181, 256};
/* set PWM width */ /* set PWM width */
TCDATA0 = 255 - logtable[brightness]; TCDATA0 = logtable[brightness];
} }
void _backlight_on(void) void _backlight_on(void)
{ {
/* configure backlight pin P0.2 as timer PWM output */
PCON0 = ((PCON0 & ~(3 << 4)) | (2 << 4));
_backlight_set_brightness(backlight_brightness); _backlight_set_brightness(backlight_brightness);
} }
void _backlight_off(void) void _backlight_off(void)
{ {
_backlight_set_brightness(MIN_BRIGHTNESS_SETTING); /* configure backlight pin P0.2 as GPIO and switch off */
PCON0 = ((PCON0 & ~(3 << 4)) | (1 << 4));
PDAT0 &= ~(1 << 2);
} }
bool _backlight_init(void) bool _backlight_init(void)
{ {
/* enable backlight pin as timer output */
PCON0 = ((PCON0 & ~(3 << 4)) | (2 << 4));
/* enable timer clock */ /* enable timer clock */
PWRCON &= ~(1 << 4); PWRCON &= ~(1 << 4);
@ -64,11 +65,11 @@ bool _backlight_init(void)
TCCMD = (1 << 1); /* TC_CLR */ TCCMD = (1 << 1); /* TC_CLR */
TCCON = (0 << 13) | /* TC_INT1_EN */ TCCON = (0 << 13) | /* TC_INT1_EN */
(0 << 12) | /* TC_INT0_EN */ (0 << 12) | /* TC_INT0_EN */
(0 << 11) | /* TC_START */ (1 << 11) | /* TC_START */
(3 << 8) | /* TC_CS = PCLK / 64 */ (3 << 8) | /* TC_CS = PCLK / 64 */
(1 << 4); /* TC_MODE_SEL = PWM mode */ (1 << 4); /* TC_MODE_SEL = PWM mode */
TCDATA1 = 255; /* set PWM period */ TCDATA1 = 256; /* set PWM period */
TCPRE = 30; /* prescaler */ TCPRE = 20; /* prescaler */
TCCMD = (1 << 0); /* TC_EN */ TCCMD = (1 << 0); /* TC_EN */
_backlight_on(); _backlight_on();