Mikroelektronika MIKROE-350 Datenbogen

330

- SOFTWARE AND HARDWARE SOLUTIONS FOR EMBEDDED WORLD

CHAPTER 6

sub procedure RS485Slave_Init(dim slave_address as byte)

Nothing.

Initializes MCU as a Slave for RS-485 communication.

Parameters : 

- 

slave_address:

Slave address 

Global variables : 
- 

RS485_rxtx_pin

- this pin is connected to RE/DE input of RS-485 

transceiver(see schematic at the bottom of this page). RE/DE signal controls 
RS-485 transceiver operation mode. Valid values: 1 (for transmitting) and 0 
(for receiving)

- 

RS485_rxtx_pin_direction

- direction of the RS-485 Transmit/Receive pin 

must be defined before using this function. 

UART HW module needs to be initialized. See UARTx_Init.

' RS485 module pinout
dim RS485_rxtx_pin as sbit  at PORTD.B2         
dim RS485_rxtx_pin_direction as sbit  at DDRD.B2
' End of RS485 module pinout

' Pass pointers to UART functions of used UART module
UART_Wr_Ptr = @UART1_Write
UART_Rd_Ptr = @UART1_Read
UART_Rdy_Ptr = @UART1_Data_Ready

UART_TX_Idle_Ptr = @UART1_TX_Idle
...
UART1_Init(9600)                    ' initialize UART module
RS485Slave_Init(160)                ' intialize MCU as a Slave

for RS-485 communication with address 160