a5966093e6
According to the reference manual, you are _forbidden_ from writing 00 to the VOS[1:0] bits in PWR_CR. Writing a 00 is automatically turned into range 2, or, 10. Attempting to then |= the bits for range 1 (01) results in the final result of choosing voltage range 3 (11). This has fairly catastrophic effects if you then attempt to switch to PLL clock at 32Mhz. Oddly, the existing code was working fine on STM32L151C6 revision W, but failing with revision V silicon. Regardless, the existing code was wrong and not following the reference manual. Further, attempting to change any power voltage range settings without the RCC enabled will have no effect, so all the higher level helper routines have added peripheral enable lines before attempting to set the range.
59 lines
1.5 KiB
C
59 lines
1.5 KiB
C
/** @defgroup pwr-file PWR
|
|
|
|
@ingroup STM32L1xx
|
|
|
|
@brief <b>libopencm3 STM32L1xx Power Control</b>
|
|
|
|
@version 1.0.0
|
|
|
|
@author @htmlonly © @endhtmlonly 2012 Karl Palsson <karlp@tweak.net.au>
|
|
|
|
@date 4 March 2013
|
|
|
|
This library supports the power control system for the
|
|
STM32L1 series of ARM Cortex Microcontrollers by ST Microelectronics.
|
|
|
|
LGPL License Terms @ref lgpl_license
|
|
*/
|
|
/*
|
|
* This file is part of the libopencm3 project.
|
|
*
|
|
* Copyright (C) 2012 Karl Palsson <karlp@tweak.net.au>
|
|
*
|
|
* This library is free software: you can redistribute it and/or modify
|
|
* it under the terms of the GNU Lesser General Public License as published by
|
|
* the Free Software Foundation, either version 3 of the License, or
|
|
* (at your option) any later version.
|
|
*
|
|
* This library 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 Lesser General Public License for more details.
|
|
*
|
|
* You should have received a copy of the GNU Lesser General Public License
|
|
* along with this library. If not, see <http://www.gnu.org/licenses/>.
|
|
*/
|
|
|
|
#include <libopencm3/stm32/pwr.h>
|
|
#include <libopencm3/stm32/rcc.h>
|
|
|
|
void pwr_set_vos_scale(vos_scale_t scale)
|
|
{
|
|
/* You are not allowed to write zeros here, don't try and optimize! */
|
|
u32 reg = PWR_CR;
|
|
reg &= ~(PWR_CR_VOS_MASK);
|
|
switch (scale) {
|
|
case RANGE1:
|
|
reg |= PWR_CR_VOS_RANGE1;
|
|
break;
|
|
case RANGE2:
|
|
reg |= PWR_CR_VOS_RANGE2;
|
|
break;
|
|
case RANGE3:
|
|
reg |= PWR_CR_VOS_RANGE3;
|
|
break;
|
|
}
|
|
PWR_CR = reg;
|
|
}
|
|
|