void I2C::init400k(void){ //todo:3 parameters for fast and a kiloHertz
init();
clearHW();
#if I2C_TRACE
stageTrace.rewind();
#endif
//cr1 as apb.init sets it up is fine
int apbRate = getClockRate();
dcb->cr2 = apbRate / 1000000; //keeps all interrupt enable stuff disabled
//compute the two fast options, choose the highest
int r1 = rate(apbRate, (25 * 400000)); //@36 = 4, 4*25 = 100 clocks = 360kHz
int r0 = rate(apbRate, (3 * 400000)); //@36 = 30, 30*3 = 90 clocks = 400kHz
if(25 * r1 > 3 * r0) {
dcb->ccr = (3 << 14) /* fast 9:16*/ | r1;
} else {
dcb->ccr = (2 << 14) /* 400kHz 1:2*/ | r0;
}
//maximum clock risetime: 3/1000000 = 3e-9 in integers without overflowing
dcb->riseTime = 1 + quanta(apbRate * 3, 10000000); //300ns: ~11 clocks at 36MHz apb clock.
//alh: suspect the +1 given in the documents is due to them truncating rather than rounding up.
//enable interrupts at NVIC:
eventIrq.prepare(); //NB: simple enable() often generates an interrupt even when all interrupts are masked, dammit! (Busy was true)
errorIrq.enable();
} /* init */
void update() {
char buf[80];
#ifdef PGMCOMOUT
// read from system;
acq200_getRoot(DROOT, SR_START, 1, "%d", &_sysstart);
acq200_getRoot(DROOT, SR_STRIDE, 1, "%d", &_sysstride);
#endif
pipin("acqcmd getNumSamples", buf, 80);
if (sscanf(buf, "ACQ32:getNumSamples=%d pre=%d post=%d",
&samples, &s0, &s2) != 3){
err("failed to read numsamples");
exit(1);
}
s0 = -s0;
getClockRate();
}
double Device::tsToTime(ULong64_t timeStamp) const
{
return (double)((timeStamp - getTimeStart()) / (double)getClockRate());
}