INTL 3:770/1 3:770/3
REPLYADDR tnp@invalid.invalid
REPLYTO 3:770/3.0 UUCP
MSGID: ca8aa255
PID: SoupGate-Win32 v1.05
Ok, this is the one destined to be an oil level sensor and I have been
working on getting a stable TCP/IP and Wi-Fi stack, which seems to have
been achieved, as its talking reliably, albeit with delay, to my most
remote Wi-Fi AP at a signal level generally around -87dbM.
That is not, however the problem (although I thought it was). The
problem seems to be that very very occasionally and as far as I can tell
*completely randomly*, it fails to return from the function listed
below. Cargo culted from the module manufacturers application notes
This is for the ultrasonic transducer module.
When it fails, all GPIO pins to and from the transducer module measure LOW.
static float get_distance()
{
int i;
absolute_time_t start;
absolute_time_t end;
static int64_t us_delay;
gpio_put(ULTRASONIC_OUT,0);
sleep_us(2);
//set output pin high
gpio_put(ULTRASONIC_OUT,1);
sleep_us(10);
gpio_put(ULTRASONIC_OUT,0); //reset the input
// wait for echo pulse start
while(!gpio_get(ULTRASONIC_IN))
;
//read clock and store
start=get_absolute_time ();
//wait for echo pin to go low;
while(gpio_get(ULTRASONIC_IN))
;
end=get_absolute_time ();
//get clock difference
us_delay=absolute_time_diff_us(start,end);
//convert to float and return it as cm
return (((float)(us_delay))*0.034/2);
}
It would seem from the pin states that it gets permanently stuck in
while(!gpio_get(ULTRASONIC_IN))
;
Which as understand it is waiting for the module (HCSR04) to *start* to
send a pulse.
Now obviously infinite loops with no termination condition under fault
conditions are poor code, but I am leaving it there until I understand
why the code is in fact hanging.
Someone online suggested that asynchronous interrupts may be the issue,
but I cant see why or what interrupts to disable.
Can anyone cast any light on this one?
Or suggest a bug hunting methodology?
--
“The fundamental cause of the trouble in the modern world today is that
the stupid are cocksure while the intelligent are full of doubt."
- Bertrand Russell
--- SoupGate-Win32 v1.05
* Origin: Agency HUB, Dunedin - New Zealand | Fido<>Usenet Gateway (3:770/3)
SEEN-BY: 15/0 19/38 90/1 105/81 106/201 128/260 129/305 135/225 153/757
SEEN-BY: 153/7715 218/700 840 220/70 226/17 30 100 227/114 229/110
SEEN-BY: 229/111 112 113 200 206 307 317 400 426 428 470 550 616 664
SEEN-BY: 229/700 266/512 267/800 282/1038 291/111 292/854 310/31 320/219
SEEN-BY: 322/757 342/200 396/45 460/58 633/280 281 412 418 420 509
SEEN-BY: 633/2744 712/848 770/1 3 100 330 340 772/210 220 230 5020/400
SEEN-BY: 5075/35
PATH: 770/3 1 633/280 229/426
|
