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#include "project.h"
#define SCL GPIO6
#define SDA GPIO7
static uint8_t
set (uint8_t sda, uint8_t scl)
{
uint8_t ret;
if (sda)
gpio_set (GPIOB, SDA);
else
gpio_clear (GPIOB, SDA);
if (scl)
gpio_set (GPIOB, SCL);
else
gpio_clear (GPIOB, SCL);
delay_us (10);
ret = (gpio_get (GPIOB, SDA) & SDA) ? 1 : 0;
return ret;
}
uint8_t
i2cb_send (uint8_t wot)
{
uint8_t i;
printf ("%02x", wot);
for (i = 0; i < 8; ++i)
{
set (wot & 0x80, 0);
set (wot & 0x80, 1);
set (wot & 0x80, 0);
wot <<= 1;
}
set (1, 0);
i = set (1, 1);
set (1, 0);
printf ("%c", i ? '!' : '.');
return i;
}
uint8_t
i2cb_send_addr (uint8_t addr, uint8_t rnw)
{
return i2cb_send (addr << 1 | rnw);
}
uint8_t
i2cb_read (uint8_t ack)
{
uint8_t i, wot = 0;
for (i = 0; i < 8; ++i)
{
wot <<= 1;
set (1, 0);
wot |= set (1, 1);
set (1, 0);
}
set (ack, 0);
set (ack, 1);
set (ack, 0);
return wot;
}
void
i2cb_start (void)
{
printf ("S");
set (1, 1);
set (0, 1);
set (0, 0);
}
void
i2cb_stop (void)
{
printf ("R\n");
set (0, 0);
set (0, 1);
set (1, 1);
}
int
i2cb_start_transaction (uint8_t a, uint8_t rnw)
{
i2cb_start ();
return i2cb_send_addr (a, rnw);
}
void
i2cb_reset (void)
{
i2cb_start ();
i2cb_stop ();
i2cb_start ();
i2cb_stop ();
}
void
i2cb_scan (void)
{
uint8_t r;
uint16_t i;
i2cb_reset ();
printf ("Probing bus\n");
for (i = 0; i < 128; ++i)
{
i2cb_start ();
i2cb_stop ();
i2cb_start ();
r = i2cb_send ((i << 1) | I2C_WRITE);
i2cb_stop ();
if (!r)
printf ("Found device at address 0x%x\n", i);
}
printf ("Done\n");
i2cb_reset ();
}
void
i2cb_init (void)
{
gpio_set_mode (GPIOB, GPIO_MODE_OUTPUT_2_MHZ, GPIO_CNF_OUTPUT_PUSHPULL,
SCL);
gpio_set_mode (GPIOB, GPIO_MODE_OUTPUT_2_MHZ, GPIO_CNF_OUTPUT_OPENDRAIN,
SDA);
set (1, 1);
#ifdef DEBUG_I2C
printf ("T11 %d:%d\n", !!(SDA_IN_REG & SDA_VAL), !!(SCL_IN_REG & SCL_VAL));
#endif
set (0, 1);
#ifdef DEBUG_I2C
printf ("T01 %d:%d\n", !!(SDA_IN_REG & SDA_VAL), !!(SCL_IN_REG & SCL_VAL));
#endif
set (1, 0);
#ifdef DEBUG_I2C
printf ("T10 %d:%d\n", !!(SDA_IN_REG & SDA_VAL), !!(SCL_IN_REG & SCL_VAL));
#endif
set (1, 1);
#ifdef DEBUG_I2C
printf ("T11 %d:%d\n", !!(SDA_IN_REG & SDA_VAL), !!(SCL_IN_REG & SCL_VAL));
#endif
}
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