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The i2c driver did not conform with i2c spec and was missing the restart. Some of the commands worked, but not every time.

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git-svn-id: svn://svn.rockbox.org/rockbox/trunk@11915 a1c6a512-1295-4272-9138-f99709370657
This commit is contained in:
Steve Gotthardt 2007-01-05 08:50:09 +00:00
parent 5668505d6b
commit ccfa883d78
1 changed files with 80 additions and 43 deletions
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115
firmware/target/arm/gigabeat/meg-fx/sc606-meg-fx.c
View file

@ -10,23 +10,28 @@
#define SLAVE_ADDRESS 0xCC #define SLAVE_ADDRESS 0xCC
#define SDA_LO GPHDAT &= ~(1 << 9) #define SDA_LO (GPHDAT &= ~(1 << 9))
#define SDA_HI GPHDAT |= (1 << 9) #define SDA_HI (GPHDAT |= (1 << 9))
#define SDA_INPUT GPHCON &= ~(3 << 18) #define SDA_INPUT (GPHCON &= ~(3 << 18))
#define SDA_OUTPUT GPHCON |= (1 << 18) #define SDA_OUTPUT (GPHCON |= (1 << 18))
#define SDA GPHDAT & (1 << 9) #define SDA (GPHDAT & (1 << 9))
#define SCL_LO GPHDAT &= ~(1 << 10) #define SCL_LO (GPHDAT &= ~(1 << 10))
#define SCL_HI GPHDAT |= (1 << 10) #define SCL_HI (GPHDAT |= (1 << 10))
#define SCL_INPUT GPHCON &= ~(3 << 20) #define SCL_INPUT (GPHCON &= ~(3 << 20))
#define SCL_OUTPUT GPHCON |= (1 << 20) #define SCL_OUTPUT (GPHCON |= (1 << 20))
#define SCL GPHDAT & (1 << 10) #define SCL (GPHDAT & (1 << 10))
#define SCL_SDA_HI GPHDAT |= (3 << 9) #define SCL_SDA_HI (GPHDAT |= (3 << 9))
/* The SC606 can clock at 400KHz: 2.5uS period -> 1.25uS half period */ /* The SC606 can clock at 400KHz: 2.5uS period -> 1.25uS half period */
/* At 300Mhz - if loop takes 10 cycles @ 3.3nS each -> 1.25uS / 30nS -> 40 */ /* The high and low times are different enough to need different timings */
#define DELAY do { volatile int _x; for(_x=0;_x<40;_x++);} while (0) /* At 300Mhz - one loop takes about 10 cycles */
#define DELAY_LO do { volatile int _x; for(_x=0;_x<20;_x++);} while (0)
#define DELAY do { volatile int _x; for(_x=0;_x<15;_x++);} while (0)
#define DELAY_HI do { volatile int _x; for(_x=0;_x<10;_x++);} while (0)
static void sc606_i2c_start(void) static void sc606_i2c_start(void)
{ {
@ -49,11 +54,9 @@ static void sc606_i2c_restart(void)
static void sc606_i2c_stop(void) static void sc606_i2c_stop(void)
{ {
SDA_LO; SDA_LO;
DELAY;
SCL_HI; SCL_HI;
DELAY; DELAY_HI;
SDA_HI; SDA_HI;
DELAY;
} }
static void sc606_i2c_ack(void) static void sc606_i2c_ack(void)
@ -61,52 +64,66 @@ static void sc606_i2c_ack(void)
SDA_LO; SDA_LO;
SCL_HI; SCL_HI;
DELAY; DELAY_HI;
SCL_LO; SCL_LO;
} }
static int sc606_i2c_getack(void) static int sc606_i2c_getack(void)
{ {
int ret = 0; int ret;
/* Don't need a delay since follows a data bit with a delay on the end */ /* Don't need a delay since follows a data bit with a delay on the end */
SDA_INPUT; /* And set to input */ SDA_INPUT; /* And set to input */
DELAY;
SCL_HI; SCL_HI;
DELAY;
if (SDA) /* ack failed */ ret = (SDA != 0); /* ack failed if SDA is not low */
ret = 1; DELAY_HI;
DELAY;
SCL_LO; SCL_LO;
DELAY; DELAY_LO;
SDA_HI;
SDA_OUTPUT; SDA_OUTPUT;
DELAY_LO;
return ret; return ret;
} }
static int sc606_i2c_outb(unsigned char byte)
static void sc606_i2c_outb(unsigned char byte)
{ {
int i; int i;
/* clock out each bit, MSB first */ /* clock out each bit, MSB first */
for (i = 0x80; i; i >>= 1) { for (i = 0x80; i; i >>= 1)
{
if (i & byte) { if (i & byte)
{
SDA_HI; SDA_HI;
} else { }
else
{
SDA_LO; SDA_LO;
} }
DELAY;
DELAY;
SCL_HI; SCL_HI;
DELAY; DELAY_HI;
SCL_LO; SCL_LO;
DELAY; DELAY_LO;
} }
return sc606_i2c_getack(); SDA_HI;
} }
static unsigned char sc606_i2c_inb(void) static unsigned char sc606_i2c_inb(void)
{ {
int i; int i;
@ -131,37 +148,57 @@ static unsigned char sc606_i2c_inb(void)
/* returns number of acks that were bad */
int sc606_write(unsigned char reg, unsigned char data) int sc606_write(unsigned char reg, unsigned char data)
{ {
int x = 0; int x = 0;
sc606_i2c_start(); sc606_i2c_start();
x += sc606_i2c_outb(SLAVE_ADDRESS);
x += 0x10 * sc606_i2c_outb(reg); sc606_i2c_outb(SLAVE_ADDRESS);
sc606_i2c_start(); x = sc606_i2c_getack();
/* sc606_i2c_restart(); */
x += 0x100 * sc606_i2c_outb(SLAVE_ADDRESS); sc606_i2c_outb(reg);
x += 0x1000 *sc606_i2c_outb(data); x += sc606_i2c_getack();
sc606_i2c_restart();
sc606_i2c_outb(SLAVE_ADDRESS);
x += sc606_i2c_getack();
sc606_i2c_outb(data);
x += sc606_i2c_getack();
sc606_i2c_stop(); sc606_i2c_stop();
return x; return x;
} }
int sc606_read(unsigned char reg, unsigned char* data) int sc606_read(unsigned char reg, unsigned char* data)
{ {
int x = 0; int x = 0;
sc606_i2c_start(); sc606_i2c_start();
sc606_i2c_outb(SLAVE_ADDRESS); sc606_i2c_outb(SLAVE_ADDRESS);
x = sc606_i2c_getack();
sc606_i2c_outb(reg); sc606_i2c_outb(reg);
x += sc606_i2c_getack();
sc606_i2c_restart(); sc606_i2c_restart();
sc606_i2c_outb(SLAVE_ADDRESS | 1); sc606_i2c_outb(SLAVE_ADDRESS | 1);
x += sc606_i2c_getack();
*data = sc606_i2c_inb(); *data = sc606_i2c_inb();
sc606_i2c_stop(); sc606_i2c_stop();
return x; return x;
} }
void sc606_init(void) void sc606_init(void)
{ {
volatile int i; volatile int i;
@ -176,7 +213,7 @@ void sc606_init(void)
/* About 400us - needs 350us */ /* About 400us - needs 350us */
for (i = 200; i; i--) for (i = 200; i; i--)
{ {
DELAY; DELAY_LO;
} }
/* Set GPH9 (SDA) and GPH10 (SCL) to 1 */ /* Set GPH9 (SDA) and GPH10 (SCL) to 1 */