You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
103 lines
2.9 KiB
103 lines
2.9 KiB
/* USB Keyboard Plus Debug Channel Example for Teensy USB Development Board
|
|
* http://www.pjrc.com/teensy/usb_keyboard.html
|
|
* Copyright (c) 2009 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:
|
|
*
|
|
* The above copyright notice and this permission notice shall be included in
|
|
* all copies or substantial portions of the Software.
|
|
*
|
|
* 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 <avr/interrupt.h>
|
|
#include "sendchar.h"
|
|
#include "usb_debug.h"
|
|
|
|
|
|
// the time remaining before we transmit any partially full
|
|
// packet, or send a zero length packet.
|
|
volatile uint8_t debug_flush_timer=0;
|
|
|
|
|
|
int8_t sendchar(uint8_t c)
|
|
{
|
|
static uint8_t previous_timeout=0;
|
|
uint8_t timeout, intr_state;
|
|
|
|
// if we're not online (enumerated and configured), error
|
|
if (!usb_configured()) return -1;
|
|
// interrupts are disabled so these functions can be
|
|
// used from the main program or interrupt context,
|
|
// even both in the same program!
|
|
intr_state = SREG;
|
|
cli();
|
|
UENUM = DEBUG_TX_ENDPOINT;
|
|
// if we gave up due to timeout before, don't wait again
|
|
if (previous_timeout) {
|
|
if (!(UEINTX & (1<<RWAL))) {
|
|
SREG = intr_state;
|
|
return -1;
|
|
}
|
|
previous_timeout = 0;
|
|
}
|
|
// wait for the FIFO to be ready to accept data
|
|
timeout = UDFNUML + 4;
|
|
while (1) {
|
|
// are we ready to transmit?
|
|
if (UEINTX & (1<<RWAL)) break;
|
|
SREG = intr_state;
|
|
// have we waited too long?
|
|
if (UDFNUML == timeout) {
|
|
previous_timeout = 1;
|
|
return -1;
|
|
}
|
|
// has the USB gone offline?
|
|
if (!usb_configured()) return -1;
|
|
// get ready to try checking again
|
|
intr_state = SREG;
|
|
cli();
|
|
UENUM = DEBUG_TX_ENDPOINT;
|
|
}
|
|
// actually write the byte into the FIFO
|
|
UEDATX = c;
|
|
// if this completed a packet, transmit it now!
|
|
if (!(UEINTX & (1<<RWAL))) {
|
|
UEINTX = 0x3A;
|
|
debug_flush_timer = 0;
|
|
} else {
|
|
debug_flush_timer = 2;
|
|
}
|
|
SREG = intr_state;
|
|
return 0;
|
|
}
|
|
|
|
// immediately transmit any buffered output.
|
|
void usb_debug_flush_output(void)
|
|
{
|
|
uint8_t intr_state;
|
|
|
|
intr_state = SREG;
|
|
cli();
|
|
if (debug_flush_timer) {
|
|
UENUM = DEBUG_TX_ENDPOINT;
|
|
while ((UEINTX & (1<<RWAL))) {
|
|
UEDATX = 0;
|
|
}
|
|
UEINTX = 0x3A;
|
|
debug_flush_timer = 0;
|
|
}
|
|
SREG = intr_state;
|
|
}
|