added system init and edited linker file

This commit is contained in:
Aria Nolan 2024-01-27 11:27:00 -05:00
parent 9588b22e20
commit 310eb52f0f
3 changed files with 40 additions and 3 deletions

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@ -7,9 +7,9 @@
*/
MEMORY
{
FLASH (rx) : ORIGIN = 0x0, LENGTH = 0x20000 /* 128K */
RAM (rwx) : ORIGIN = 0x10000000, LENGTH = 0x2000 /* 8K */
RAM2 (rwx) : ORIGIN = 0x20000000, LENGTH = 0x2000 /* 8K */
FLASH (rx) : ORIGIN = 0x0, LENGTH = 0x8000 /* 32K */
RAM (rwx) : ORIGIN = 0x1FFFFC00, LENGTH = 0x400 /* 1K */
RAM2 (rwx) : ORIGIN = 0x20000000, LENGTH = 0xC00 /* 3K */
}
/* Linker script to place sections and symbol values. Should be used together

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@ -30,6 +30,11 @@
ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
POSSIBILITY OF SUCH DAMAGE.
---------------------------------------------------------------------------*/
/* CHANGING DEFINES */
#define __STARTUP_COPY_MULTIPLE
#define __STARTUP_CLEAR_BSS_MULTIPLE
.syntax unified
.arch armv6-m

32
sysinit.c Normal file
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@ -0,0 +1,32 @@
#include "MKL05Z4.h"
#define MCG_C4_DC0_25PMAX_MID (MCG_C4_DMX32_MASK | (1 << MCG_C4_DRST_DRS_SHIFT))
// comments here are pretty poor since I barly understand what's going on
void SystemInit()
{
__asm("cpsid i");
SIM_COPC = 0; // disable COP watchdog timer
/***** set 48-MHz clock, 24-MHz bus clock ******/
SIM_SCGC5 |= 0x00000200; // port A mask
PORTA_PCR3 = PORT_PCR_ISF_MASK;
PORTA_PCR4 = PORT_PCR_ISF_MASK;
SIM_CLKDIV1 = 1 << SIM_CLKDIV1_OUTDIV4_SHIFT; // changes clock divider
MCG_C2 = MCG_C2_EREFS0_MASK; // osc settings
OSC0_CR = OSC_CR_ERCLKEN_MASK; // external ref clock
MCG_C1 = MCG_C1_IRCLKEN_MASK;
while (MCG_S & MCG_S_OSCINIT0_MASK); // wait for osc to become stable
while (!(MCG_S & MCG_S_IREFST_MASK)); // wait for FLL and external clock to match
// preserve FCTRIM and SCFTRIM
MCG_C4 = ((MCG_C4 & -MCG_C4_DRST_DRS_MASK) | MCG_C4_DC0_25PMAX_MID);
// wait for output of FLL to be selected
while (!(MCG_S & MCG_S_CLKST_MASK));
/****************************/
}