Hi,
Today I noticed that my response to the question below was not kind enough,
especially for those new to PSoC.
So I wrote a couple of simpler samples for UART input char into array using CY8CKIT-059.
One is using polling and the other is using an interrupt.
I hope these are easier to understand comparing with the sample I suggested in the question.
(1) Polling mode (without using interrupt)
Note: This actually utilizes the component's internal interrupt, but from the view point of the programmer, it's a polling mode. (I hope)
schematic
UART config
pins
main.c
==============
#include "project.h"
#include "stdio.h"
#define CR '\r'
#define NL '\n'
#define BS '\b'
#define RX_BUF_LEN 64
char rx_buf[RX_BUF_LEN+1] ; /* 1byte for NULL */
void print(char *str)
{
UART_PutString(str) ;
}
void printc(char c)
{
UART_PutChar(c) ;
}
int line_received = 0 ;
int rx_index = 0 ;
int get_line(void)
{
uint8_t c ;
while((line_received == 0) && (UART_GetRxBufferSize() > 0)) {
c = UART_GetByte() ;
switch(c) {
case 0x00:
case 0xFF:
break ;
case BS: /* backspace */
if (rx_index > 1) {
rx_index-- ;
rx_buf[rx_index] = 0 ;
print("\b \b") ;
}
break ;
case NL:
case CR:
printc(c) ;
rx_buf[rx_index] = 0 ;
rx_index = 0 ;
line_received = 1 ;
break ;
default:
printc(c) ;
rx_buf[rx_index] = c ;
rx_index++ ;
if (rx_index >= RX_BUF_LEN) { /* buffer overflow */
rx_buf[RX_BUF_LEN] = 0 ; /* terminate the string */
line_received = -1 ; /* not 0 but not 1 as this is error */
rx_index = 0 ;
}
}
}
return(line_received) ;
}
void prompt(void)
{
print("> ") ;
}
int main(void)
{
CyGlobalIntEnable; /* Enable global interrupts. */
UART_Start() ;
print("\x1b[2J\x1b[;H") ; /* clear screen */
print("UART polling test ") ;
snprintf(rx_buf, RX_BUF_LEN, "(%s %s)\n", __DATE__, __TIME__) ;
print(rx_buf) ;
prompt() ;
for(;;)
{
if (get_line()) {
print("Line: ") ;
print(rx_buf) ;
print("\n") ;
line_received = 0 ;
prompt() ;
}
}
}
==============
Tera Term log
(2) Using an interrupt
schematic
UART config
pins
Note: pins are same with (1)
main.c
==================
#include "project.h"
#include "stdio.h"
#define CR '\r'
#define NL '\n'
#define BS '\b'
#define RX_BUF_LEN 64
volatile char rx_buf[RX_BUF_LEN] ;
#define STR_LEN 32
char str[STR_LEN+1] ; /* 1 byte for NULL */
void print(char *str)
{
UART_PutString(str) ;
while(UART_GetTxBufferSize() > 0) ;
}
void printc(char c)
{
UART_PutChar(c) ;
}
volatile int line_received = 0 ;
volatile int rx_write_index = 0 ;
int rx_read_index = 0 ;
int str_index = 0 ;
CY_ISR(uart_isr)
{
uint32_t status ;
uint8_t c ;
status = UART_ReadRxStatus() ;
if (status & UART_RX_STS_FIFO_NOTEMPTY){
c = UART_ReadRxData() ;
if ((c != 0x00) && (c != 0xFF)) {
rx_buf[rx_write_index] = c ;
rx_write_index = (rx_write_index + 1) % RX_BUF_LEN ;
}
}
}
int get_line(void)
{
uint8_t c ;
while((line_received == 0)&&(rx_read_index != rx_write_index)) {
c = rx_buf[rx_read_index] ;
switch(c) {
case 0x00:
case 0xFF:
break ;
case BS: /* backspace */
if (str_index > 0) {
str_index-- ;
str[str_index] = 0 ;
print("\b \b") ;
}
break ;
case NL:
case CR:
printc(c) ;
str[str_index] = 0 ;
str_index = 0 ;
line_received = 1 ;
break ;
default:
printc(c) ;
str[str_index] = c ;
str_index++ ;
if (str_index >= STR_LEN) { /* buffer overflow */
str[STR_LEN] = 0 ; /* terminate the string */
line_received = -1 ; /* not 0 but not 1 as this is error */
str_index = 0 ;
}
}
rx_read_index = (rx_read_index + 1) % RX_BUF_LEN ;
}
return(line_received) ;
}
void prompt(void)
{
print("> ") ;
}
int main(void)
{
CyGlobalIntEnable; /* Enable global interrupts. */
uart_rx_int_ClearPending() ;
uart_rx_int_StartEx(uart_isr) ;
UART_Start() ;
print("\x1b[2J\x1b[;H") ; /* clear screen */
print("UART interrupt test ") ;
snprintf(str, STR_LEN, "(%s %s)\n", __DATE__, __TIME__) ;
print(str) ;
prompt() ;
for(;;)
{
if (get_line()) {
print("Line: ") ;
print(str) ;
print("\n") ;
line_received = 0 ;
prompt() ;
}
}
}
==================
Tera Term log
moto
P.S. (edited) UART config screen shots were added.
