[2.0.x] Add support for LPC1769 at 120 MHz (#9423)

Marlin/src/HAL/HAL_LPC1768/SoftwareSPI.h

@@ -0,0 +1,50 @@
+/**
+ * Marlin 3D Printer Firmware
+ * Copyright (C) 2016 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
+ *
+ * Based on Sprinter and grbl.
+ * Copyright (C) 2011 Camiel Gubbels / Erik van der Zalm
+ *
+ * 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 3 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, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#ifndef _SOFTWARE_SPI_H_
+#define _SOFTWARE_SPI_H_
+
+  #include "pinmapping.h"
+
+  // --------------------------------------------------------------------------
+  // software SPI
+  // --------------------------------------------------------------------------
+
+  /**
+   * This software SPI runs at multiple rates. The SD software provides an index
+   * (spiRate) of 0-6. The mapping is:
+   *     0 - about 5 MHz peak (6 MHz on LPC1769)
+   *     1-2 - about 2 MHz peak
+   *     3 - about 1 MHz peak
+   *     4 - about 500 kHz peak
+   *     5 - about 250 kHz peak
+   *     6 - about 125 kHz peak
+   */
+
+  void swSpiBegin(pin_t sck_pin, pin_t miso_pin, pin_t mosi_pin);
+
+  // Returns the spi_speed value to be passed to swSpiTransfer
+  uint8_t swSpiInit(uint8_t spiRate, pin_t sck_pin, pin_t mosi_pin);
+
+  uint8_t swSpiTransfer(uint8_t b, uint8_t spi_speed, pin_t sck_pin, pin_t miso_pin, pin_t mosi_pin);
+
+#endif // _SOFTWARE_SPI_H_