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Minimize risk of stepper routine interrupt blocking by reorganizing 

the routine to move the G-code line length from the command queue
to the planner queue.
This commit is contained in:
bubnikv 2018-01-20 14:37:22 +01:00
parent b5f8b1d97c
commit 9e534c1990
2 changed files with 31 additions and 9 deletions
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36
Firmware/Marlin_main.cpp
View File

@ -1409,8 +1409,12 @@ void loop()
#endif //SDSUPPORT
if (! cmdbuffer_front_already_processed && buflen)
{
cli();
{
// ptr points to the start of the block currently being processed.
// The first character in the block is the block type.
char *ptr = cmdbuffer + bufindr;
if (*ptr == CMDBUFFER_CURRENT_TYPE_SDCARD) {
// To support power panic, move the lenght of the command on the SD card to a planner buffer.
union {
struct {
char lo;
@ -1419,14 +1423,28 @@ void loop()
uint16_t value;
} sdlen;
sdlen.value = 0;
if (CMDBUFFER_CURRENT_TYPE == CMDBUFFER_CURRENT_TYPE_SDCARD) {
sdlen.lohi.lo = cmdbuffer[bufindr + 1];
sdlen.lohi.hi = cmdbuffer[bufindr + 2];
{
// This block locks the interrupts globally for 3.25 us,
// which corresponds to a maximum repeat frequency of 307.69 kHz.
// This blocking is safe in the context of a 10kHz stepper driver interrupt
// or a 115200 Bd serial line receive interrupt, which will not trigger faster than 12kHz.
cli();
// Reset the command to something, which will be ignored by the power panic routine,
// so this buffer length will not be counted twice.
*ptr ++ = CMDBUFFER_CURRENT_TYPE_TO_BE_REMOVED;
// Extract the current buffer length.
sdlen.lohi.lo = *ptr ++;
sdlen.lohi.hi = *ptr;
// and pass it to the planner queue.
planner_add_sd_length(sdlen.value);
sei();
}
cmdqueue_pop_front();
planner_add_sd_length(sdlen.value);
sei();
}
}
// Now it is safe to release the already processed command block. If interrupted by the power panic now,
// this block's SD card length will not be counted twice as its command type has been replaced
// by CMDBUFFER_CURRENT_TYPE_TO_BE_REMOVED.
cmdqueue_pop_front();
}
host_keepalive();
}
}

4
Firmware/cmdqueue.h
View File

@ -18,6 +18,10 @@
#define CMDBUFFER_CURRENT_TYPE_UI 3
// Command in cmdbuffer was generated by another G-code.
#define CMDBUFFER_CURRENT_TYPE_CHAINED 4
// Command has been processed and its SD card length has been possibly pushed
// to the planner queue, but not yet removed from the cmdqueue.
// This is a temporary state to reduce stepper interrupt locking time.
#define CMDBUFFER_CURRENT_TYPE_TO_BE_REMOVED 5
// How much space to reserve for the chained commands
// of type CMDBUFFER_CURRENT_TYPE_CHAINED,