Сообщество » Примеры программ

h1. Work with UART (C)

Observe transmit and receive messages via UART more details (in С).

Configuration UART on transmission and reception message in C looks like simple as in Assembler of multicellular processor. 

Besides this in C for working with UART available usefull functions and macros, such as sending value int type, sending string,

sending definition array of data memory.

In code examples use UART library, which must required:

<pre>

#include <uart.h>

</pre>

h2. а) Transmit via UART

h3. 1. Configurate UART on transmission

First step - create structure (all elements of structure see in uart.h).

<pre>

UART_InitTypeDef UART_InitStructure;

</pre>

Initialize needed parameters (other parameters initialize as null).

<pre>

    UART_InitStructure.BaudRate = 38400; //baudrate

    UART_InitStructure.TypeParity = 0x00000000; //type parity control

    UART_InitStructure.Parity = 0x00000000; //allow parity control

    UART_InitStructure.FlowControl = 0x00000000; //allow dataflow control

    UART_InitStructure.Mode = 0x00000002; //allow transmit  

</pre>

Initialize for UART0:

<pre>

uart_init(UART0, &UART_InitStructure);

</pre>

For UART3:

<pre>

uart_init(UART3, &UART_InitStructure);

</pre>

h3. 2. Allow alternative port functions

For UART0:

<pre>

GPIOB->BPS = 0x00000F00;

</pre>

For UART3:

<pre>

GPIOD->BPS = 0x00000F00;

</pre>

h3. 3. Check transmitter FIFO on full 

For UART0:

<pre>

while(UART_FIFO_TX_FULL(UART0) == 1);

</pre>

For UART3:

<pre>

while(UART_FIFO_TX_FULL(UART3) == 1);

</pre>

h3. 4. Transmit byte via UART

For UART0:

<pre>

UART_SEND_BYTE(0xAB, UART0);

</pre>

For UART3:

<pre>

UART_SEND_BYTE(0xAB, UART3);

</pre>

As a result you can get simple example - transmission byte via UART with baudrate 38400 kbit/s:

For UART0:

<pre>

#include <HDL51001_ccf.h>

#include <uart.h>

void main()

{

   UART_InitTypeDef UART_InitStructure;

    UART_InitStructure.BaudRate = 38400; //baudrate

    UART_InitStructure.TypeParity = 0x00000000; //type parity control

    UART_InitStructure.Parity = 0x00000000; //allow parity control

    UART_InitStructure.FlowControl = 0x00000000; //allow dataflow control

    UART_InitStructure.Mode = 0x00000002; //allow transmit

    uart_init(UART0, &UART_InitStructure);  

    GPIOB->BPS = 0x00000F00;

    while(UART_FIFO_TX_FULL(UART0) == 1);

    UART_SEND_BYTE(0xAB, UART0);

}

</pre>

For UART3 example is analogie, replace port B on D and UART0 on UART3.

Transmitted byte you can receive with PC application - any COM port monitor, setting on data with 1 stop-bit,

baudrate 38400 kbit/s, data word - 8 bit.

h2. б) Receive via UART

For reception via UART:

h3. 1. Execute 1,2 under letter а)

h3. 2. Check receiver FIFO for new data

For UART0:

<pre>

while(UART_NEW_DATA(UART0) == 0);

</pre>

For UART3:

<pre>

while(UART_NEW_DATA(UART3) == 0);

</pre>

h3. 3. Get data

For UART0:

<pre>

rbyte = UART_GET_BYTE(UART0);

</pre>

For UART3:

<pre>

rbyte = UART_GET_BYTE(UART3);

</pre>

h2. API functions UART:

Observe every functions, which declared in uart.h

<pre>1) void uart_init(UART_TypeDef *UART, UART_InitTypeDef* UART_InitStruct)</pre>

Function _uart_init()_ initialize definition number of UART.

UART - available value: UART0, UART1, UART2, UART3

UART_InitStruct - structure, contain configuration elements UART

<pre>2) void DM2UART(UART_TypeDef *UART, int start_address, int size_block)</pre>

Функция _DM2UART ()_ output sector data memory via UART in a little endian format.

UART - available value: UART0, UART1, UART2, UART3

start_address - start data memory address

size_block - size data sector

<pre>3) void uart_send_str(char *str, UART_TypeDef *UART)</pre>

Function _uart_send_str()_ output string via UART.

UART - available value: UART0, UART1, UART2, UART3

str - string

<pre>4) void uart_send_int(int str, UART_TypeDef *UART)</pre>

Function _uart_send_int()_ output variable int type via UART.

UART - available value: UART0, UART1, UART2, UART3

str - variable int type

h3. Note:

In library versions before 01.04.13 needed before DM2UART (), uart_send_int()

use consructions:

<pre>

while(UART_FIFO_TX_EMPTY(UART0) == 0);

</pre>

In library versions after 01.04.13 you can use functions independently.