#include <string.h>
#include "asf.h"
#include "stdio_serial.h"
#include "conf_board.h"
#include "conf_clock.h"
#include "conf_example.h"
/** Size of the receive buffer used by the PDC, in bytes. */
#define BUFFER_SIZE 100
/** USART PDC transfer type definition. */
#define PDC_TRANSFER 1
/** USART FIFO transfer type definition. */
#define BYTE_TRANSFER 0
/** Max buffer number. */
#define MAX_BUF_NUM 1
/** All interrupt mask. */
#define ALL_INTERRUPT_MASK 0xffffffff
/** Timer counter frequency in Hz. */
#define TC_FREQ 1
#define STRING_EOL "\r"
#define STRING_HEADER "-- USART Serial Example --\r\n" \
"-- "BOARD_NAME" --\r\n" \
"-- Compiled: "__DATE__" "__TIME__" --"STRING_EOL
/** Receive buffer. */
static uint8_t gs_puc_buffer[2][BUFFER_SIZE];
/** Next Receive buffer. */
static uint8_t gs_puc_nextbuffer[2][BUFFER_SIZE];
/** Current bytes in buffer. */
static uint32_t gs_ul_size_buffer = BUFFER_SIZE;
/** Current bytes in next buffer. */
static uint32_t gs_ul_size_nextbuffer = BUFFER_SIZE;
/** Byte mode read buffer. */
static uint32_t gs_ul_read_buffer = 0;
/** Current transfer mode. */
static uint8_t gs_uc_trans_mode = PDC_TRANSFER;
/** Buffer number in use. */
static uint8_t gs_uc_buf_num = 0;
/** PDC data packet. */
pdc_packet_t g_st_packet, g_st_nextpacket;
/** Pointer to PDC register base. */
Pdc *g_p_pdc;
/** Flag of one transfer end. */
static uint8_t g_uc_transend_flag = 0;
/**
* \brief Interrupt handler for USART. Echo the bytes received and start the
* next receive.
*/
void USART_Handler(void)
{
uint32_t ul_status;
/* Read USART Status. */
ul_status = usart_get_status(BOARD_USART);
if (gs_uc_trans_mode == PDC_TRANSFER) {
/* Receive buffer is full. */
if (ul_status & US_CSR_RXBUFF) {
/* Disable timer. */
tc_stop(TC0, 0);
/* Echo back buffer. */
g_st_packet.ul_addr =
(uint32_t)gs_puc_buffer[gs_uc_buf_num];
g_st_packet.ul_size = gs_ul_size_buffer;
g_st_nextpacket.ul_addr =
(uint32_t)gs_puc_nextbuffer[gs_uc_buf_num];
g_st_nextpacket.ul_size = gs_ul_size_nextbuffer;
pdc_tx_init(g_p_pdc, &g_st_packet, &g_st_nextpacket);
if (g_uc_transend_flag) {
gs_ul_size_buffer = BUFFER_SIZE;
gs_ul_size_nextbuffer = BUFFER_SIZE;
g_uc_transend_flag = 0;
}
gs_uc_buf_num = MAX_BUF_NUM - gs_uc_buf_num;
/* Restart read on buffer. */
g_st_packet.ul_addr =
(uint32_t)gs_puc_buffer[gs_uc_buf_num];
g_st_packet.ul_size = BUFFER_SIZE;
g_st_nextpacket.ul_addr =
(uint32_t)gs_puc_nextbuffer[ gs_uc_buf_num];
g_st_nextpacket.ul_size = BUFFER_SIZE;
pdc_rx_init(g_p_pdc, &g_st_packet, &g_st_nextpacket);
/* Restart timer. */
tc_start(TC0, 0);
}
} else {
/* Transfer without PDC. */
if (ul_status & US_CSR_RXRDY) {
usart_getchar(BOARD_USART, (uint32_t *)&gs_ul_read_buffer);
usart_write(BOARD_USART, gs_ul_read_buffer);
}
}
}
/**
* \brief Interrupt handler for TC0. Record the number of bytes received,
* and then restart a read transfer on the USART if the transfer was stopped.
*/
void TC0_Handler(void)
{
uint32_t ul_status;
uint32_t ul_byte_total = 0;
/* Read TC0 Status. */
ul_status = tc_get_status(TC0, 0);
/* RC compare. */
if (((ul_status & TC_SR_CPCS) == TC_SR_CPCS) &&
(gs_uc_trans_mode == PDC_TRANSFER)) {
/* Flush PDC buffer. */
ul_byte_total = BUFFER_SIZE - pdc_read_rx_counter(g_p_pdc);
if ((ul_byte_total != 0) && (ul_byte_total != BUFFER_SIZE)) {
/* Log current size. */
g_uc_transend_flag = 1;
if (pdc_read_rx_next_counter(g_p_pdc) == 0) {
gs_ul_size_buffer = BUFFER_SIZE;
gs_ul_size_nextbuffer = ul_byte_total;
} else {
gs_ul_size_buffer = ul_byte_total;
gs_ul_size_nextbuffer = 0;
}
/* Trigger USART Receive Buffer Full Interrupt. */
pdc_rx_clear_cnt(g_p_pdc);
}
}
}
/**
* \brief Configure USART in normal (serial rs232) mode, asynchronous,
* 8 bits, 1 stop bit, no parity, 115200 bauds and enable its transmitter
* and receiver.
*/
static void configure_usart(void)
{
const sam_usart_opt_t usart_console_settings = {
BOARD_USART_BAUDRATE,
US_MR_CHRL_8_BIT,
US_MR_PAR_NO,
US_MR_NBSTOP_1_BIT,
US_MR_CHMODE_NORMAL,
/* This field is only used in IrDA mode. */
0
};
/* Enable the peripheral clock in the PMC. */
sysclk_enable_peripheral_clock(BOARD_ID_USART);
/* Configure USART in serial mode. */
usart_init_rs232(BOARD_USART, &usart_console_settings,
sysclk_get_cpu_hz());
/* Disable all the interrupts. */
usart_disable_interrupt(BOARD_USART, ALL_INTERRUPT_MASK);
/* Enable the receiver and transmitter. */
usart_enable_tx(BOARD_USART);
usart_enable_rx(BOARD_USART);
/* Configure and enable interrupt of USART. */
NVIC_EnableIRQ(USART_IRQn);
}
/**
* \brief Configure Timer Counter 0 (TC0) to generate an interrupt every 200ms.
* This interrupt will be used to flush USART input and echo back.
*/
static void configure_tc(void)
{
uint32_t ul_div;
uint32_t ul_tcclks;
static uint32_t ul_sysclk;
/* Get system clock. */
ul_sysclk = sysclk_get_cpu_hz();
/* Configure PMC. */
pmc_enable_periph_clk(ID_TC0);
/* Configure TC for a 50Hz frequency and trigger on RC compare. */
tc_find_mck_divisor(TC_FREQ, ul_sysclk, &ul_div, &ul_tcclks, ul_sysclk);
tc_init(TC0, 0, ul_tcclks | TC_CMR_CPCTRG);
tc_write_rc(TC0, 0, (ul_sysclk / ul_div) / TC_FREQ);
/* Configure and enable interrupt on RC compare. */
NVIC_EnableIRQ((IRQn_Type)ID_TC0);
tc_enable_interrupt(TC0, 0, TC_IER_CPCS);
}
/**
* Configure UART for debug message output.
*/
static void configure_console(void)
{
const usart_serial_options_t uart_serial_options = {
.baudrate = CONF_UART_BAUDRATE,
.paritytype = CONF_UART_PARITY
};
/* Configure console UART. */
sysclk_enable_peripheral_clock(CONSOLE_UART_ID);
stdio_serial_init(CONF_UART, &uart_serial_options);
}
/**
* \brief Reset the TX & RX, and clear the PDC counter.
*/
static void usart_clear(void)
{
/* Reset and disable receiver & transmitter. */
usart_reset_rx(BOARD_USART);
usart_reset_tx(BOARD_USART);
/* Clear PDC counter. */
g_st_packet.ul_addr = 0;
g_st_packet.ul_size = 0;
g_st_nextpacket.ul_addr = 0;
g_st_nextpacket.ul_size = 0;
pdc_rx_init(g_p_pdc, &g_st_packet, &g_st_nextpacket);
/* Enable receiver & transmitter. */
usart_enable_tx(BOARD_USART);
usart_enable_rx(BOARD_USART);
}
/**
* \brief Display main menu.
*/
static void display_main_menu(void)
{
puts("-- Menu Choices for this example --\r\n"
"-- s: Switch mode for USART between PDC and without PDC.--\r\n"
"-- m: Display this menu again.--\r");
}
/**
* \brief Application entry point for usart_serial example.
*
* \return Unused (ANSI-C compatibility).
*/
int main(void)
{
uint8_t uc_char;
uint8_t uc_flag;
/* Initialize the SAM system. */
sysclk_init();
board_init();
/* Configure UART for debug message output. */
configure_console();
/* Output example information. */
puts(STRING_HEADER);
/* Configure USART. */
configure_usart();
/* Get board USART PDC base address. */
g_p_pdc = usart_get_pdc_base(BOARD_USART);
/* Enable receiver and transmitter. */
pdc_enable_transfer(g_p_pdc, PERIPH_PTCR_RXTEN | PERIPH_PTCR_TXTEN);
/* Configure TC. */
configure_tc();
/* Start receiving data and start timer. */
g_st_packet.ul_addr = (uint32_t)gs_puc_buffer[gs_uc_buf_num];
g_st_packet.ul_size = BUFFER_SIZE;
g_st_nextpacket.ul_addr = (uint32_t)gs_puc_nextbuffer[gs_uc_buf_num];
g_st_nextpacket.ul_size = BUFFER_SIZE;
pdc_rx_init(g_p_pdc, &g_st_packet, &g_st_nextpacket);
puts("-- Start to echo serial inputs -- \r\n"
"-I- Default Transfer with PDC \r\n"
"-I- Press 's' to switch transfer mode \r");
gs_uc_trans_mode = PDC_TRANSFER;
usart_disable_interrupt(BOARD_USART, US_IDR_RXRDY);
usart_enable_interrupt(BOARD_USART, US_IER_RXBUFF);
tc_start(TC0, 0);
while (1) {
uc_char = 0;
uc_flag = uart_read(CONSOLE_UART, &uc_char);
if (!uc_flag) {
switch (uc_char) {
case 's':
case 'S':
if (gs_uc_trans_mode == PDC_TRANSFER) {
/* Transfer to no PDC communication mode. */
/* Disable PDC controller. */
pdc_disable_transfer(g_p_pdc,
PERIPH_PTCR_RXTDIS | PERIPH_PTCR_TXTDIS);
/* Disable the RXBUFF interrupt. */
usart_disable_interrupt(BOARD_USART, US_IDR_RXBUFF);
/* Clear USART controller. */
usart_clear();
/* Enable the RXRDY interrupt. */
usart_enable_interrupt(BOARD_USART, US_IER_RXRDY);
gs_uc_trans_mode = BYTE_TRANSFER;
puts("-I- Transfer without PDC \r");
} else if (gs_uc_trans_mode == BYTE_TRANSFER) {
pdc_enable_transfer(g_p_pdc,
PERIPH_PTCR_RXTEN | PERIPH_PTCR_TXTEN);
/* Clear USART controller. */
usart_clear();
/* Reset pdc current buffer size. */
gs_ul_size_buffer = BUFFER_SIZE;
gs_ul_size_nextbuffer = BUFFER_SIZE;
gs_uc_buf_num = 0;
/* Start receiving data. */
g_st_packet.ul_addr =
(uint32_t)gs_puc_buffer[gs_uc_buf_num];
g_st_packet.ul_size = BUFFER_SIZE;
g_st_nextpacket.ul_addr =
(uint32_t)gs_puc_nextbuffer[gs_uc_buf_num];
g_st_nextpacket.ul_size = BUFFER_SIZE;
pdc_rx_init(g_p_pdc, &g_st_packet, &g_st_nextpacket);
/* Transfer to PDC communication mode, disable RXRDY interrupt and enable RXBUFF interrupt. */
usart_disable_interrupt(BOARD_USART, US_IER_RXRDY);
usart_enable_interrupt(BOARD_USART, US_IER_RXBUFF);
gs_uc_trans_mode = PDC_TRANSFER;
puts("-I- Transfer with PDC \r");
}
break;
case 'm':
case 'M':
display_main_menu();
break;
default:
break;
}
}
}
}
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