static unsigned char read_reg(unsigned char addr)
{
unsigned char r;
i2c_start_cond();
i2c_write(0x40);
i2c_write(addr);
i2c_start_cond();
i2c_write(0x41);
r = i2c_read(0);
i2c_stop_cond();
return r;
}
static void write_reg(unsigned char addr, unsigned char val)
{
i2c_start_cond();
i2c_write(0x40);
i2c_write(addr);
i2c_write(val);
i2c_stop_cond();
}
void set_dac_level(int level)
{
if(!i2c_init()) {
printf("I2C init failed\n");
return;
}
i2c_start_cond();
if(!i2c_write(0x90))
printf("DAC not detected\n");
i2c_write(0x2f);
i2c_write((level & 0xff0) >> 4);
i2c_write((level & 0x00f) << 4);
i2c_stop_cond();
}
// Write a byte to I2C bus. Return 0 if ack by the slave.
bool i2c_write_byte(bool send_start,
bool send_stop,
unsigned char byte) {
unsigned bit;
bool nack;
if (send_start) {
i2c_start_cond();
}
for (bit = 0; bit < 8; bit++) {
i2c_write_bit((byte & 0x80) != 0);
byte <<= 1;
}
nack = i2c_read_bit();
if (send_stop) {
i2c_stop_cond();
}
return nack;
}
