For ARMv6, which is what the raspi is, you go through CP15 to create barriers: //memory barriers for ARMv6. These 3 are special and non-privileged. #ifndef barrierdefs #define barrierdefs //raspi is ARMv6. It does not have ARMv7 DMB/DSB/ISB, so go through CP15. #define isb() __asm__ __volatile__ (&q...

<t>To get PPS working, one needs to add PPS support into a driver that receives an interrupt. Adding PPS code to a driver that is already interrupt driven, such as a PC parallel port, is about an hour's work. I'm slow. I test.<br/> <br/> The question will be whether there already is pin-change inter...