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zero_gravi |
// #################################################################################################
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// # < neo430_timer.c - Timer helper functions > #
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// # ********************************************************************************************* #
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// # BSD 3-Clause License #
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// # #
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// # Copyright (c) 2020, Stephan Nolting. All rights reserved. #
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// # #
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// # Redistribution and use in source and binary forms, with or without modification, are #
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// # permitted provided that the following conditions are met: #
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// # #
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// # 1. Redistributions of source code must retain the above copyright notice, this list of #
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// # conditions and the following disclaimer. #
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// # #
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// # 2. Redistributions in binary form must reproduce the above copyright notice, this list of #
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// # conditions and the following disclaimer in the documentation and/or other materials #
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// # provided with the distribution. #
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// # #
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// # 3. Neither the name of the copyright holder nor the names of its contributors may be used to #
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// # endorse or promote products derived from this software without specific prior written #
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// # permission. #
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// # #
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// # THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS #
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// # OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF #
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// # MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE #
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// # COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, #
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// # EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE #
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// # GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED #
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// # AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING #
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// # NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED #
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// # OF THE POSSIBILITY OF SUCH DAMAGE. #
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// # ********************************************************************************************* #
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// # The NEO430 Processor - https://github.com/stnolting/neo430 #
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// #################################################################################################
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#include "neo430.h"
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#include "neo430_timer.h"
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/* ------------------------------------------------------------
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* INFO Activate Timer
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* ------------------------------------------------------------ */
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void neo430_timer_enable(void) {
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TMR_CT |= (1<<TMR_CT_EN);
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}
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/* ------------------------------------------------------------
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* INFO Deactivate (and reset) Timer
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* ------------------------------------------------------------ */
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void neo430_timer_disable(void) {
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TMR_CT = 0;
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}
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/* ------------------------------------------------------------
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* INFO Start Timer
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* ------------------------------------------------------------ */
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void neo430_timer_run(void) {
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TMR_CT |= (1<<TMR_CT_RUN);
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}
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/* ------------------------------------------------------------
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* INFO Pause Timer
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* ------------------------------------------------------------ */
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void neo430_timer_pause(void) {
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TMR_CT &= ~(1<<TMR_CT_RUN);
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}
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/* ------------------------------------------------------------
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* INFO Configure timer period
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* PARAM Timer frequency in Hz (1 ... F_CPU/2), uint16_t pointer to store computed THRES value
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* RETURN 0 if successful, 0xff if error
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* ------------------------------------------------------------ */
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uint8_t neo430_timer_config_freq(uint32_t f_timer, uint16_t *thres) {
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uint32_t clock = CLOCKSPEED_32bit;
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uint32_t ticks = (clock / f_timer) >> 1; // divide by lowest prescaler (= f/2)
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uint8_t prsc = 0;
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if (ticks == 0)
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return 0xff; // frequency too high!
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// find prescaler
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while(prsc < 8) {
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if (ticks <= 0x0000ffff) {
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break;
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}
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else {
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if ((prsc == 2) || (prsc == 4)) {
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ticks >>= 3;
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}
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else {
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ticks >>= 1;
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}
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prsc++;
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}
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}
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TMR_THRES = (uint16_t)ticks;
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*thres = (uint16_t)ticks;
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TMR_CT &= ~(7<<TMR_CT_PRSC0); // clear prsc bits
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TMR_CT |= (prsc<<TMR_CT_PRSC0);
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return 0;
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}
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