mirror of
https://github.com/eddyem/stm32samples.git
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62 lines
2.0 KiB
C
62 lines
2.0 KiB
C
/*
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* This file is part of the as3935 project.
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* Copyright 2026 Edward V. Emelianov <edward.emelianoff@gmail.com>.
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include "spi.h"
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#include "hardware.h"
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#include "commproto.h"
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// CR1 register default values
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// Fpclk/64
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static const uint32_t SPI_CR1 = SPI_CR1_MSTR | SPI_CR1_BR_2 | SPI_CR1_BR_0 | SPI_CR1_SSM | SPI_CR1_SSI | SPI_CR1_CPHA /* | SPI_CR1_CPOL*/;
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spiStatus SPI_status = SPI_NOTREADY;
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uint8_t as3935_channel = 0;
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void spi_setup(){
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// master, no slave select, BR=F/16, CPOL/CPHA - polarity.
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SPI1->CR1 = SPI_CR1;
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SPI_status = SPI_READY;
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SPI1->CR1 |= SPI_CR1_SPE; // enable SPI
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}
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volatile uint32_t wctr;
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#define WAITX(x) do{wctr = 0; while((x) && (++wctr < 360000)) IWDG->KR = IWDG_REFRESH; if(wctr==360000) return -1;}while(0)
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/**
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* @brief SPI_transmit - transmit data and receive new one
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* @param buf - data to transmit/receive
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* @param len - its length
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* @return amount of transmitted data or -1 if error
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*/
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uint8_t SPI_transmit(uint8_t *buf, uint8_t len){
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if(!buf || !len) return 0; // bad data format
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if(SPI_status != SPI_READY) return 0; // spi not ready to transmit data
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CS(as3935_channel);
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for(uint8_t x = 0; x < len; ++x){
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WAITX(!(SPI1->SR & SPI_SR_TXE));
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SPI1->DR = buf[x];
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WAITX(!(SPI1->SR & SPI_SR_BSY));
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WAITX(!(SPI1->SR & SPI_SR_RXNE));
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buf[x] = SPI1->DR;
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}
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CS_OFF();
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return len;
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}
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