"USB_SOF_HOOK" where examples or shared projects using this?
Posted: Tue Mar 26, 2013 9:46 am
Hi."USB_SOF_HOOK" - please give example or links to shared projects using this?
/* #ifdef __ASSEMBLER__
* macro myAssemblerMacro
* in YL, TCNT0
* sts timer0Snapshot, YL
* endm
* #endif
* #define USB_SOF_HOOK myAssemblerMacro
* This macro (if defined) is executed in the assembler module when a
* Start Of Frame condition is detected. It is recommended to define it to
* the name of an assembler macro which is defined here as well so that more
* than one assembler instruction can be used. The macro may use the register
* YL and modify SREG. If it lasts longer than a couple of cycles, USB messages
* immediately after an SOF pulse may be lost and must be retried by the host.
* What can you do with this hook? Since the SOF signal occurs exactly every
* 1 ms (unless the host is in sleep mode), you can use it to tune OSCCAL in
* designs running on the internal RC oscillator.
* Please note that Start Of Frame detection works only if D- is wired to the
* interrupt, not D+. THIS IS DIFFERENT THAN MOST EXAMPLES!