Mikroelektronika MIKROE-350 Fiche De Données

352

- SOFTWARE AND HARDWARE SOLUTIONS FOR EMBEDDED WORLD

CHAPTER 6

sub function Soft_UART_Init(dim baud_rate as longword, dim
inverted 

as byte) as 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
dim Soft_UART_Rx_Pin           as sbit at PIND.B0        
dim Soft_UART_Tx_Pin           as sbit at PORTD.B1       
dim Soft_UART_Rx_Pin_Direction as sbit at DDRD.B0
dim Soft_UART_Tx_Pin_Direction as sbit at DDRD.B1
' Soft UART connections

' Initialize Software UART communication on pins Rx, Tx, at 9600
bps
Soft_UART_Init(9600, 0)