diff options
Diffstat (limited to 'protocol/pjrc/usb_debug.c')
| -rw-r--r-- | protocol/pjrc/usb_debug.c | 102 |
1 files changed, 102 insertions, 0 deletions
diff --git a/protocol/pjrc/usb_debug.c b/protocol/pjrc/usb_debug.c new file mode 100644 index 0000000000..c1e6f6544b --- /dev/null +++ b/protocol/pjrc/usb_debug.c @@ -0,0 +1,102 @@ +/* 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; +} |