machine/esp32c3: handle defaults for I2C configuration

Signed-off-by: deadprogram <ron@hybridgroup.com>

src/machine/machine_esp32c3.go

@@ -626,6 +626,16 @@ const (
 )
 
 func (i2c *I2C) Configure(config I2CConfig) error {
+	if config.Frequency == 0 {
+		config.Frequency = 400 * KHz
+	}
+	if config.SCL == 0 {
+		config.SCL = SCL_PIN
+	}
+	if config.SDA == 0 {
+		config.SDA = SDA_PIN
+	}
+
 	i2c.initClock(config)
 	i2c.initNoiseFilter()
 	i2c.initPins(config)
@@ -907,7 +917,7 @@ func (i2c *I2C) transmit(addr uint16, cmd []i2cCommand, timeoutMS int) error {
 // bytes and stores them in r, and generates a stop condition on the bus.
 func (i2c *I2C) Tx(addr uint16, w, r []byte) (err error) {
 	// timeout in microseconds.
-	const timeout = 100 * 1000 // 40ms is a reasonable time for a real-time system.
+	const timeout = 40 // 40ms is a reasonable time for a real-time system.
 
 	cmd := make([]i2cCommand, 0, 8)
 	cmd = append(cmd, i2cCommand{cmd: i2cCMD_RSTART})
@@ -921,3 +931,7 @@ func (i2c *I2C) Tx(addr uint16, w, r []byte) (err error) {
 
 	return i2c.transmit(addr, cmd, timeout)
 }
+
+func (i2c *I2C) SetBaudRate(br uint32) error {
+	return nil
+}