Arnaud VALLEY / Mbed 2 deprecated Pinscape_Controller_V2_arnoz

Mirror with some correction

Dependencies:   mbed FastIO FastPWM USBDevice

mbed_Fixes/KLXX_us_ticker_fix.c@116:7a67265d7c19, 2021-10-01 (annotated)

Committer:
arnoz
Date:
Fri Oct 01 08:19:46 2021 +0000
Revision:
116:7a67265d7c19
Parent:
79:682ae3171a08 
- Correct information regarding your last merge

Who changed what in which revision?

UserRevisionLine numberNew contents of line
mjr 79:682ae3171a08 1 #include <stddef.h>
mjr 79:682ae3171a08 2 #include "us_ticker_api.h"
mjr 79:682ae3171a08 3
mjr 79:682ae3171a08 4 // Bug fix: if scheduling an event in the past, schedule it for
mjr 79:682ae3171a08 5 // the very near future rather than invoking the handler directly.
mjr 79:682ae3171a08 6 // For Tickers and other recurring events, invoking the handler
mjr 79:682ae3171a08 7 // can cause significant recursion, since the handler might try
mjr 79:682ae3171a08 8 // to schedule the next event, which will end up back here, which
mjr 79:682ae3171a08 9 // will call the handler again, and so on. Forcing the event
mjr 79:682ae3171a08 10 // into the future prevents this recursion and ensures bounded
mjr 79:682ae3171a08 11 // stack use. The effect will be the same either way: the handler
mjr 79:682ae3171a08 12 // will be called late, since we can't actually travel back in time
mjr 79:682ae3171a08 13 // and call it in the past. But this way we don't blow the stack
mjr 79:682ae3171a08 14 // if we have a high-frequency recurring event that has gotten
mjr 79:682ae3171a08 15 // significantly behind (because of a long period with interrupts
mjr 79:682ae3171a08 16 // disabled, say).
mjr 79:682ae3171a08 17 extern void $Super$$us_ticker_set_interrupt(timestamp_t);
mjr 79:682ae3171a08 18 void $Sub$$us_ticker_set_interrupt(timestamp_t timestamp)
mjr 79:682ae3171a08 19 {
mjr 79:682ae3171a08 20 // If the event was in the past, schedule it for almost (but not
mjr 79:682ae3171a08 21 // quite) immediately. This prevents the base version from recursing
mjr 79:682ae3171a08 22 // into the handler; instead, we'll schedule an interrupt as for any
mjr 79:682ae3171a08 23 // other future event.
mjr 79:682ae3171a08 24 int tcur = us_ticker_read();
mjr 79:682ae3171a08 25 int delta = (int)((uint32_t)timestamp - tcur);
mjr 79:682ae3171a08 26 if (delta <= 0)
mjr 79:682ae3171a08 27 timestamp = tcur + 2;
mjr 79:682ae3171a08 28
mjr 79:682ae3171a08 29 // call the base handler
mjr 79:682ae3171a08 30 $Super$$us_ticker_set_interrupt(timestamp);
mjr 79:682ae3171a08 31 }