Copyright (C) 2011 Georg Ottinger
This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License
as published by the Free Software Foundation; either version 2
of the License, or (at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
CLK->SWCR |= CLK_SWCR_SWEN; //finalize clock source change
CLK->SWR = (u8)CLK_SOURCE_HSE; //choose external Oszilator
while(!(CLK->SWCR & CLK_SWCR_SWIF)) //wait for Clock to settle
// CLK->SWCR |= CLK_SWCR_SWEN; //finalize clock source change
CLK->CKDIVR = 0; // prescaler for Internal Clock and CPU Clock is 1
//the internal Bus and the CPU should now run at the speed of the external Oszillator
void InitSPI(SPI_BaudRatePrescaler_TypeDef prescaler)
while(SPI->SR & SPI_FLAG_BSY);
SPI->CR1 = SPI_FIRSTBIT_MSB|(u8)prescaler|SPI_MODE_MASTER|SPI_CLOCKPOLARITY_LOW|SPI_CLOCKPHASE_1EDGE;
SPI->CR2 = 0x03; //SSM and SSI
SPI->CR1 |= 0x40; //Enable SPI;
SPI->DR = 0;