devs/foxbox
1
0
Fork 0
forked from len0rd/rockbox
Code Pull requests Activity

Optimized the timing for the delay and changed the startup delay.

Browse source 
git-svn-id: svn://svn.rockbox.org/rockbox/trunk@11896 a1c6a512-1295-4272-9138-f99709370657
This commit is contained in:
Steve Gotthardt 2007-01-04 09:26:32 +00:00
parent e4e42707fe
commit 26496ce72f
1 changed files with 8 additions and 7 deletions
Download patch file Download diff file Expand all files Collapse all files

15
firmware/target/arm/gigabeat/meg-fx/sc606-meg-fx.c
View file

@ -25,8 +25,8 @@
#define SCL_SDA_HI GPHDAT |= (3 << 9)
/* The SC606 can clock at 400KHz: 2.5uS period -> 1.25uS half period */
/* At 300Mhz - if loop takes 6 cycles @ 3.3nS each -> 1.25uS / 20nS -> 63 */
#define DELAY do { volatile int _x; for(_x=0;_x<63;_x++);} while (0)
/* At 300Mhz - if loop takes 10 cycles @ 3.3nS each -> 1.25uS / 30nS -> 40 */
#define DELAY do { volatile int _x; for(_x=0;_x<40;_x++);} while (0)
static void sc606_i2c_start(void)
{
@ -164,6 +164,8 @@ int sc606_read(unsigned char reg, unsigned char* data)
void sc606_init(void)
{
volatile int i;
/* Set GPB2 (EN) to 1 */
GPBCON = (GPBCON & ~(3<<4)) | 1<<4;
@ -172,11 +174,10 @@ void sc606_init(void)
/* OFF GPBDAT &= ~(1 << 2); */
/* About 400us - needs 350us */
DELAY;
DELAY;
DELAY;
DELAY;
DELAY;
for (i = 200; i; i--)
{
DELAY;
}
/* Set GPH9 (SDA) and GPH10 (SCL) to 1 */
GPHUP &= ~(3<<9);