micropython/teensy/core/usb_serial.c

274 wiersze
7.0 KiB
C

/* Teensyduino Core Library
* http://www.pjrc.com/teensy/
* Copyright (c) 2013 PJRC.COM, LLC.
*
* Permission is hereby granted, free of charge, to any person obtaining
* a copy of this software and associated documentation files (the
* "Software"), to deal in the Software without restriction, including
* without limitation the rights to use, copy, modify, merge, publish,
* distribute, sublicense, and/or sell copies of the Software, and to
* permit persons to whom the Software is furnished to do so, subject to
* the following conditions:
*
* 1. The above copyright notice and this permission notice shall be
* included in all copies or substantial portions of the Software.
*
* 2. If the Software is incorporated into a build system that allows
* selection among a list of target devices, then similar target
* devices manufactured by PJRC.COM must be included in the list of
* target devices and selectable in the same manner.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
* BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
* ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*/
#include "usb_dev.h"
#include "usb_serial.h"
#include "core_pins.h" // for yield()
//#include "HardwareSerial.h"
#include <string.h> // for memcpy()
// defined by usb_dev.h -> usb_desc.h
#if defined(CDC_STATUS_INTERFACE) && defined(CDC_DATA_INTERFACE)
uint32_t usb_cdc_line_coding[2];
volatile uint8_t usb_cdc_line_rtsdtr=0;
volatile uint8_t usb_cdc_transmit_flush_timer=0;
static usb_packet_t *rx_packet=NULL;
static usb_packet_t *tx_packet=NULL;
static volatile uint8_t tx_noautoflush=0;
#define TRANSMIT_FLUSH_TIMEOUT 5 /* in milliseconds */
// get the next character, or -1 if nothing received
int usb_serial_getchar(void)
{
unsigned int i;
int c;
if (!rx_packet) {
if (!usb_configuration) return -1;
rx_packet = usb_rx(CDC_RX_ENDPOINT);
if (!rx_packet) return -1;
}
i = rx_packet->index;
c = rx_packet->buf[i++];
if (i >= rx_packet->len) {
usb_free(rx_packet);
rx_packet = NULL;
} else {
rx_packet->index = i;
}
return c;
}
// peek at the next character, or -1 if nothing received
int usb_serial_peekchar(void)
{
if (!rx_packet) {
if (!usb_configuration) return -1;
rx_packet = usb_rx(CDC_RX_ENDPOINT);
if (!rx_packet) return -1;
}
if (!rx_packet) return -1;
return rx_packet->buf[rx_packet->index];
}
// number of bytes available in the receive buffer
int usb_serial_available(void)
{
int count;
count = usb_rx_byte_count(CDC_RX_ENDPOINT);
if (rx_packet) count += rx_packet->len - rx_packet->index;
return count;
}
// read a block of bytes to a buffer
int usb_serial_read(void *buffer, uint32_t size)
{
uint8_t *p = (uint8_t *)buffer;
uint32_t qty, count=0;
while (size) {
if (!usb_configuration) break;
if (!rx_packet) {
rx:
rx_packet = usb_rx(CDC_RX_ENDPOINT);
if (!rx_packet) break;
if (rx_packet->len == 0) {
usb_free(rx_packet);
goto rx;
}
}
qty = rx_packet->len - rx_packet->index;
if (qty > size) qty = size;
memcpy(p, rx_packet->buf + rx_packet->index, qty);
p += qty;
count += qty;
size -= qty;
rx_packet->index += qty;
if (rx_packet->index >= rx_packet->len) {
usb_free(rx_packet);
rx_packet = NULL;
}
}
return count;
}
// discard any buffered input
void usb_serial_flush_input(void)
{
usb_packet_t *rx;
if (!usb_configuration) return;
if (rx_packet) {
usb_free(rx_packet);
rx_packet = NULL;
}
while (1) {
rx = usb_rx(CDC_RX_ENDPOINT);
if (!rx) break;
usb_free(rx);
}
}
// Maximum number of transmit packets to queue so we don't starve other endpoints for memory
#define TX_PACKET_LIMIT 8
// When the PC isn't listening, how long do we wait before discarding data? If this is
// too short, we risk losing data during the stalls that are common with ordinary desktop
// software. If it's too long, we stall the user's program when no software is running.
#define TX_TIMEOUT_MSEC 70
#if F_CPU == 168000000
#define TX_TIMEOUT (TX_TIMEOUT_MSEC * 1100)
#elif F_CPU == 144000000
#define TX_TIMEOUT (TX_TIMEOUT_MSEC * 932)
#elif F_CPU == 120000000
#define TX_TIMEOUT (TX_TIMEOUT_MSEC * 764)
#elif F_CPU == 96000000
#define TX_TIMEOUT (TX_TIMEOUT_MSEC * 596)
#elif F_CPU == 72000000
#define TX_TIMEOUT (TX_TIMEOUT_MSEC * 512)
#elif F_CPU == 48000000
#define TX_TIMEOUT (TX_TIMEOUT_MSEC * 428)
#elif F_CPU == 24000000
#define TX_TIMEOUT (TX_TIMEOUT_MSEC * 262)
#endif
// When we've suffered the transmit timeout, don't wait again until the computer
// begins accepting data. If no software is running to receive, we'll just discard
// data as rapidly as Serial.print() can generate it, until there's something to
// actually receive it.
static uint8_t transmit_previous_timeout=0;
// transmit a character. 0 returned on success, -1 on error
int usb_serial_putchar(uint8_t c)
{
return usb_serial_write(&c, 1);
}
int usb_serial_write(const void *buffer, uint32_t size)
{
uint32_t len;
uint32_t wait_count;
const uint8_t *src = (const uint8_t *)buffer;
uint8_t *dest;
tx_noautoflush = 1;
while (size > 0) {
if (!tx_packet) {
wait_count = 0;
while (1) {
if (!usb_configuration) {
tx_noautoflush = 0;
return -1;
}
if (usb_tx_packet_count(CDC_TX_ENDPOINT) < TX_PACKET_LIMIT) {
tx_noautoflush = 1;
tx_packet = usb_malloc();
if (tx_packet) break;
tx_noautoflush = 0;
}
if (++wait_count > TX_TIMEOUT || transmit_previous_timeout) {
transmit_previous_timeout = 1;
return -1;
}
yield();
}
}
transmit_previous_timeout = 0;
len = CDC_TX_SIZE - tx_packet->index;
if (len > size) len = size;
dest = tx_packet->buf + tx_packet->index;
tx_packet->index += len;
size -= len;
while (len-- > 0) *dest++ = *src++;
if (tx_packet->index >= CDC_TX_SIZE) {
tx_packet->len = CDC_TX_SIZE;
usb_tx(CDC_TX_ENDPOINT, tx_packet);
tx_packet = NULL;
}
usb_cdc_transmit_flush_timer = TRANSMIT_FLUSH_TIMEOUT;
}
tx_noautoflush = 0;
return 0;
}
void usb_serial_flush_output(void)
{
if (!usb_configuration) return;
tx_noautoflush = 1;
if (tx_packet) {
usb_cdc_transmit_flush_timer = 0;
tx_packet->len = tx_packet->index;
usb_tx(CDC_TX_ENDPOINT, tx_packet);
tx_packet = NULL;
} else {
usb_packet_t *tx = usb_malloc();
if (tx) {
usb_cdc_transmit_flush_timer = 0;
usb_tx(CDC_TX_ENDPOINT, tx);
} else {
usb_cdc_transmit_flush_timer = 1;
}
}
tx_noautoflush = 0;
}
void usb_serial_flush_callback(void)
{
if (tx_noautoflush) return;
if (tx_packet) {
tx_packet->len = tx_packet->index;
usb_tx(CDC_TX_ENDPOINT, tx_packet);
tx_packet = NULL;
} else {
usb_packet_t *tx = usb_malloc();
if (tx) {
usb_tx(CDC_TX_ENDPOINT, tx);
} else {
usb_cdc_transmit_flush_timer = 1;
}
}
}
#endif // CDC_STATUS_INTERFACE && CDC_DATA_INTERFACE