Configures and initializes the software UART module.

Software UART routines use Delay_Cyc routine. If requested baud rate is too low then calculated parameter for calling Delay_Cyc exceeds Delay_Cyc argument range.

If requested baud rate is too high then rounding error of Delay_Cyc argument corrupts Software UART timings.

• baud_rate: requested baudrate. Maximum baud rate depends on the MCU’s clock and working conditions
• inverted: if set to non-zero value, indicates inverted logic on output

• 2 - error, requested baud rate is too low
• 1 - error, requested baud rate is too high
• 0 - successful initialization

External dependencies of the library from the top of the page must be defined before using this function.

// Software UART module connections
sbit Soft_Uart_RX_Pin at GPIO_PIN26_Bit;
sbit Soft_Uart_TX_Pin at GPIO_PIN27_Bit;
// End Software UART module connections
...
error = Soft_UART_Init(4800, 0);        // Initialize Soft UART at 4800 bps

The Software UART library implements time-based activities, so interrupts need to be disabled when using it.

The function receives a byte via software UART.

This is a blocking function call (waits for start bit). Programmer can unblock it by calling Soft_UART_Break routine.

• error: Error flag. Error code is returned through this variable. Values :
• 0 - no error
• 1 - stop bit error
• 255 - user abort, Soft_UART_Break called

Byte received via UART.

Software UART must be initialized before using this function. See the Soft_UART_Init routine.

char data_;
char error;
...
// wait until data is received
do
  data = Soft_UART_Read(&error);
while (error);

// Now we can work with data:
if (data_) {...}

The Software UART library implements time-based activities, so interrupts need to be disabled when using it.

This routine sends one byte via the Software UART bus.

• udata: data to be sent.

Nothing.

Software UART must be initialized before using this function. See the Soft_UART_Init routine.

Be aware that during transmission, software UART is incapable of receiving data – data transfer protocol must be set in such a way to prevent loss of information.

char some_byte = 0x0A;
...
// Write a byte via Soft UART
Soft_UART_Write(some_byte);

The Software UART library implements time-based activities, so interrupts need to be disabled when using it.

Soft_UART_Read is blocking routine and it can block the program flow. Calling Soft_UART_Break routine from the interrupt will unblock the program execution. This mechanism is similar to WDT.

None.

Nothing.

The Software UART library implements time-based activities, so interrupts need to be disabled when using it.