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Added possibility to enable internal pull-up resistors with i2c_pullups(boolean)

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This commit is contained in:
Karl Kangur 2016-02-20 16:40:25 +01:00
parent e12077513f
commit 0ee04e985a
2 changed files with 13 additions and 2 deletions
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11
extras/i2c/i2c.c
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@ -36,16 +36,23 @@
#define CLK_STRETCH (10)
static bool started;
static bool pullups;
static uint8_t g_scl_pin;
static uint8_t g_sda_pin;
void i2c_init(uint8_t scl_pin, uint8_t sda_pin)
{
started = false;
pullups = false;
g_scl_pin = scl_pin;
g_sda_pin = sda_pin;
}
void i2c_pullups(bool enable)
{
pullups = enable;
}
static void i2c_delay(void)
{
sdk_os_delay_us(CLK_HALF_PERIOD_US);
@ -54,14 +61,14 @@ static void i2c_delay(void)
// Set SCL as input and return current level of line, 0 or 1
static bool read_scl(void)
{
gpio_enable(g_scl_pin, GPIO_INPUT);
gpio_enable(g_scl_pin, pullups ? GPIO_INPUT_PULLUP : GPIO_INPUT);
return gpio_read(g_scl_pin); // Clock high, valid ACK
}
// Set SDA as input and return current level of line, 0 or 1
static bool read_sda(void)
{
gpio_enable(g_sda_pin, GPIO_INPUT);
gpio_enable(g_sda_pin, pullups ? GPIO_INPUT_PULLUP : GPIO_INPUT);
// TODO: Without this delay we get arbitration lost in i2c_stop
i2c_delay();
return gpio_read(g_sda_pin); // Clock high, valid ACK

4
extras/i2c/i2c.h
View file

@ -49,3 +49,7 @@ bool i2c_slave_read(uint8_t slave_addr, uint8_t data, uint8_t *buf, uint32_t len
// devices where the i2c_slave_[read|write] functions above are of no use.
void i2c_start(void);
void i2c_stop(void);
// Use internal pull-up resistors instead of external ones,
// by default they are disabled.
void i2c_pullups(bool enable);