Mikroelektronika MIKROE-742 데이터 시트

365

- SOFTWARE AND HARDWARE SOLUTIONS FOR EMBEDDED WORLD

CHAPTER 6

function Soft_UART_Init(baud_rate: dword; inverted: byte): byte; 

- 

2

- error, requested baud rate is too low 

- 

1

- error, requested baud rate is too high 

- 

0

- successfull initialization 

Configures and initializes the software UART module.

Parameters : 

- 

baud_rate

: baud rate to be set. Maximum baud rate depends on the MCU’s 

clock and working conditions. 

- 

inverted

: inverted output flag. When set to a non-zero value, inverted logic 

on output is used. 

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

Delay_Cyc

exceeeds Delay_Cyc argu-

ment range.

If requested baud rate is too high then rounding error of 

Delay_Cyc

argument

corrupts Software UART timings.

Global variables:

- 

Soft_UART_Rx_Pin

: Receiver pin 

- 

Soft_UART_Tx_Pin

: Transmiter pin 

- 

Soft_UART_Rx_Pin_Direction

: Direction of the Receiver pin 

- 

Soft_UART_Tx_Pin_Direction

: Direction of the Transmiter pin 

must be defined before using this function.

// Soft UART connections
var Soft_UART_Rx_Pin           : sbit at PIND.B0;        
var Soft_UART_Tx_Pin           : sbit at PORTD.B1;       
var Soft_UART_Rx_Pin_Direction : sbit at DDRD.B0;
var Soft_UART_Tx_Pin_Direction : sbit at DDRD.B1;
// Soft UART connections

...
// Initialize Software UART communication on pins Rx, Tx, at 9600
bps

Soft_UART_Init(9600, 0);