90 lines
2.7 KiB
C++
90 lines
2.7 KiB
C++
/**
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* Marlin 3D Printer Firmware
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* Copyright (C) 2016, 2017 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
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*
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* Based on Sprinter and grbl.
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* Copyright (C) 2011 Camiel Gubbels / Erik van der Zalm
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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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*/
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/**
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* Software SPI functions originally from Arduino Sd2Card Library
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* Copyright (C) 2009 by William Greiman
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*/
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/**
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* For TARGET_LPC1768
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*/
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#ifdef TARGET_LPC1768
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#include "../../inc/MarlinConfig.h"
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// --------------------------------------------------------------------------
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// Software SPI
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// --------------------------------------------------------------------------
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/**
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* This software SPI runs at multiple rates. The SD software provides an index
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* (spiRate) of 0-6. The mapping is:
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* 0 - about 5 MHz peak (6 MHz on LPC1769)
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* 1-2 - about 2 MHz peak
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* 3 - about 1 MHz peak
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* 4 - about 500 kHz peak
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* 5 - about 250 kHz peak
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* 6 - about 125 kHz peak
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*/
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uint8_t swSpiTransfer(uint8_t b, const uint8_t spi_speed, const pin_t sck_pin, const pin_t miso_pin, const pin_t mosi_pin) {
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for (uint8_t i = 0; i < 8; i++) {
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if (spi_speed == 0) {
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WRITE(mosi_pin, !!(b & 0x80));
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WRITE(sck_pin, HIGH);
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b <<= 1;
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if (miso_pin >= 0 && READ(miso_pin)) b |= 1;
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WRITE(sck_pin, LOW);
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}
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else {
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const uint8_t state = (b & 0x80) ? HIGH : LOW;
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for (uint8_t j = 0; j < spi_speed; j++)
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WRITE(mosi_pin, state);
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for (uint8_t j = 0; j < spi_speed + (miso_pin >= 0 ? 0 : 1); j++)
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WRITE(sck_pin, HIGH);
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b <<= 1;
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if (miso_pin >= 0 && READ(miso_pin)) b |= 1;
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for (uint8_t j = 0; j < spi_speed; j++)
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WRITE(sck_pin, LOW);
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}
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}
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return b;
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}
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void swSpiBegin(const pin_t sck_pin, const pin_t miso_pin, const pin_t mosi_pin) {
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SET_OUTPUT(sck_pin);
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if (VALID_PIN(miso_pin)) SET_INPUT(miso_pin);
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SET_OUTPUT(mosi_pin);
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}
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uint8_t swSpiInit(const uint8_t spiRate, const pin_t sck_pin, const pin_t mosi_pin) {
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WRITE(mosi_pin, HIGH);
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WRITE(sck_pin, LOW);
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return (SystemCoreClock == 120000000 ? 44 : 38) / POW(2, 6 - MIN(spiRate, 6));
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}
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#endif // TARGET_LPC1768
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