blob: 97590184a508dd02b92cbcf87477e7eba88f6bf2 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
|
#include <avr/interrupt.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;
// transmit a character. 0 returned on success, -1 on error
int8_t usb_debug_putchar(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;
}
|
