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uart_ow: Better error handling in corner cases

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Signed-off-by: Brendan Le Foll <brendan.le.foll@intel.com>
This commit is contained in:
Brendan Le Foll
2016-04-15 12:03:32 +01:00
parent 4a52ad6c4f
commit c41c3b41d5
4 changed files with 72 additions and 44 deletions
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12
api/mraa/uart_ow.h
View File

@@ -117,18 +117,18 @@ mraa_result_t mraa_uart_ow_stop(mraa_uart_ow_context dev);
* Read a byte from the 1-wire bus
*
* @param dev uart_ow context
* @return the byte read
* @return the byte read or -1 for error
*/
uint8_t mraa_uart_ow_read_byte(mraa_uart_ow_context dev);
int mraa_uart_ow_read_byte(mraa_uart_ow_context dev);
/**
* Write a byte to a 1-wire bus
*
* @param dev uart_ow context
* @param byte the byte to write to the bus
* @return the byte read back during the time slot
* @return the byte read back during the time slot or -1 for error
*/
uint8_t mraa_uart_ow_write_byte(mraa_uart_ow_context dev, uint8_t byte);
int mraa_uart_ow_write_byte(mraa_uart_ow_context dev, uint8_t byte);
/**
* Write a bit to a 1-wire bus and read a bit corresponding to the
@@ -137,9 +137,9 @@ uint8_t mraa_uart_ow_write_byte(mraa_uart_ow_context dev, uint8_t byte);
*
* @param dev uart_ow context
* @param bit the bit to write to the bus
* @return the bit read back during the time slot
* @return the bit read back during the time slot or -1 for error
*/
uint8_t mraa_uart_ow_bit(mraa_uart_ow_context dev, uint8_t bit);
int mraa_uart_ow_bit(mraa_uart_ow_context dev, uint8_t bit);
/**
* Send a reset pulse to the 1-wire bus and test for device presence

25
api/mraa/uart_ow.hpp
View File

@@ -46,6 +46,7 @@ class UartOW
* UartOW Constructor, takes a pin number which will map directly to the
* linux uart number, this 'enables' the uart, nothing more
*
* @throws std::invalid_argument in case of error
* @param uart the index of the uart to use
*/
UartOW(int uart)
@@ -61,6 +62,7 @@ class UartOW
* UartOW Constructor, takes a string to the path of the serial
* interface that is needed.
*
* @throws std::invalid_argument in case of error
* @param path the file path for the UART to use
*/
UartOW(std::string path)
@@ -96,24 +98,35 @@ class UartOW
/**
* Read a byte from the 1-wire bus
*
* @throws std::invalid_argument in case of error
* @return the byte read
*/
uint8_t
readByte()
{
return mraa_uart_ow_read_byte(m_uart);
int res = mraa_uart_ow_read_byte(m_uart);
if (res == -1) {
throw std::invalid_argument("Unknown UART_OW error");
}
return (uint8_t) res;
}
/**
* Write a byte to a 1-wire bus
*
* @param byte the byte to write to the bus
*
* @throws std::invalid_argument in case of error
* @return the byte read back during the time slot
*/
uint8_t
writeByte(uint8_t byte)
{
return mraa_uart_ow_write_byte(m_uart, byte);
int res = mraa_uart_ow_write_byte(m_uart, byte);
if (res == -1) {
throw std::invalid_argument("Unknown UART_OW error");
}
return (uint8_t) res;
}
/**
@@ -122,13 +135,17 @@ class UartOW
* and RX together with a diode, forming a loopback.
*
* @param bit the bit to write to the bus
* @throws std::invalid_argument in case of error
* @return the bit read back during the time slot
*/
bool
writeBit(bool bit)
{
uint8_t rv = mraa_uart_ow_bit(m_uart, (bit) ? 1 : 0);
return ((rv) ? true : false);
int res = mraa_uart_ow_bit(m_uart, (bit) ? 1 : 0);
if (res == -1) {
throw std::invalid_argument("Unknown UART_OW error");
}
return ((res) ? true : false);
}
/**