From: Svenne Krap Date: Thu, 4 Nov 2010 19:51:04 +0000 (+0100) Subject: First try at sysinit X-Git-Url: http://git.asbjorn.it/?a=commitdiff_plain;ds=inline;h=0783008344c324bec7a236b5d410701b340ff412;p=rapper.git First try at sysinit --- diff --git a/lpc176x/main.c b/lpc176x/main.c new file mode 100644 index 0000000..79e7934 --- /dev/null +++ b/lpc176x/main.c @@ -0,0 +1,6 @@ +#include "sysinit.c" + +int main(int argc, char **argv) { + sysinit(); + return 0; +} diff --git a/lpc176x/sysinit.c b/lpc176x/sysinit.c new file mode 100644 index 0000000..c64c591 --- /dev/null +++ b/lpc176x/sysinit.c @@ -0,0 +1,82 @@ +void sysinit() { + // xtal_freq = 12000000; + + volatile int *scs; + scs = (int *)0x400fc1a0; + // enable main oscillator + *scs = 0x20; + + // wait for oscillator to get ready + while ((*scs & (1<<6)) == 0); + + volatile int *cclkcfg; + cclkcfg = (int *)0x400FC104; + // set clockdivider to 1/4x + *cclkcfg = 0x03; + + // peripheral clocks (all set to 1/4x cclk) + volatile int *pclksel0, *pclksel1; + pclksel0=(int *)0x400FC1A8; + *pclksel0 = 0; + pclksel1=(int *)0x400FC1AC; + *pclksel1 = 0; + + // main clock set (pll0) + volatile int *clksrcsel; + clksrcsel = (int *)0x400FC10C; + *clksrcsel = 0x01; + + volatile int *pll0con, *pll0stat, *pll0feed, *pll0cfg; + pll0con=(int*)0x400FC080; + pll0stat=(int *)0x400FC088; + // pll0feed : feed 0xAA followed by 0x55 to feed + pll0feed=(int *)0x400FC08C; + pll0cfg=(int *)0x400FC084; + + // FORMULA = FCCO = (2 * M * FIN) / N + // as Xtal (FIN) is 12MHz, N = 6 , M = 25 gives 100 MHz + // as both msel and nsel stores "N-1" store 24 and 5 + *pll0cfg = 24 | (5 << 16); + + // feed to set clock + *pll0feed = 0xaa; + *pll0feed = 0x55; + + + // enable pll0 + *pll0con = 0x01; + *pll0feed = 0xaa; + *pll0feed = 0x55; + + // wait for enable + while (!(*pll0stat & (1<<26))); + + // lock pll0 + *pll0con = 0x03; + *pll0feed = 0xaa; + *pll0feed = 0x55; + + // wait for lock + while (!(*pll0stat & ((1<<25) | (1<<24)))); + + volatile int *pll1con, *pll1cfg, *pll1stat, *pll1feed; + pll1con=(int *)0x400FC0A0; + pll1cfg=(int *)0x400FC0A4; + pll1stat=(int *)0x400FC0A8; + pll1feed=(int *)0x400FC0AC; + + // setup pll1 (multiplier 4, divider 6) + *pll1cfg = 3 | (0x01 << 5); + + // enable pll1 + *pll1con = 0x01; + *pll1feed = 0xaa; + *pll1feed = 0x55; + while (!(*pll1stat & (1<<10))); + + // connect pll1 + *pll1con = 0x03; + *pll1feed = 0xaa; + *pll1feed = 0x55; + while (!(*pll1stat & ((1<< 9) | (1<< 8)))); +} diff --git a/lpc176x/sysinit.h b/lpc176x/sysinit.h new file mode 100644 index 0000000..c409b71 --- /dev/null +++ b/lpc176x/sysinit.h @@ -0,0 +1 @@ +void sysinit();