Starting with Stock BTT-Config and Old Configs as Backup

Marlin/src/HAL/shared/eeprom_if_spi.cpp

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+/**
+ * Marlin 3D Printer Firmware
+ * Copyright (c) 2020 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 <https://www.gnu.org/licenses/>.
+ *
+ */
+
+/**
+ * Platform-independent Arduino functions for SPI EEPROM.
+ * Enable USE_SHARED_EEPROM if not supplied by the framework.
+ */
+
+#include "../../inc/MarlinConfig.h"
+
+#if ENABLED(SPI_EEPROM)
+
+#include "eeprom_if.h"
+
+void eeprom_init() {}
+
+#if ENABLED(USE_SHARED_EEPROM)
+
+#define CMD_WREN  6   // WREN
+#define CMD_READ  2   // WRITE
+#define CMD_WRITE 2   // WRITE
+
+#ifndef EEPROM_WRITE_DELAY
+  #define EEPROM_WRITE_DELAY    7
+#endif
+
+static void _eeprom_begin(uint8_t * const pos, const uint8_t cmd) {
+  const uint8_t eeprom_temp[3] = {
+    cmd,
+    (unsigned(pos) >> 8) & 0xFF,  // Address High
+     unsigned(pos)       & 0xFF   // Address Low
+  };
+  WRITE(SPI_EEPROM1_CS, HIGH);    // Usually free already
+  WRITE(SPI_EEPROM1_CS, LOW);     // Activate the Bus
+  spiSend(SPI_CHAN_EEPROM1, eeprom_temp, 3);
+                                  // Leave the Bus in-use
+}
+
+uint8_t eeprom_read_byte(uint8_t *pos) {
+  _eeprom_begin(pos, CMD_READ);   // Set read location and begin transmission
+
+  const uint8_t v = spiRec(SPI_CHAN_EEPROM1); // After READ a value sits on the Bus
+
+  WRITE(SPI_EEPROM1_CS, HIGH);    // Done with device
+
+  return v;
+}
+
+void eeprom_write_byte(uint8_t *pos, uint8_t value) {
+  const uint8_t eeprom_temp = CMD_WREN;
+  WRITE(SPI_EEPROM1_CS, LOW);
+  spiSend(SPI_CHAN_EEPROM1, &eeprom_temp, 1); // Write Enable
+
+  WRITE(SPI_EEPROM1_CS, HIGH);      // Done with the Bus
+  delay(1);                         // For a small amount of time
+
+  _eeprom_begin(pos, CMD_WRITE);    // Set write address and begin transmission
+
+  spiSend(SPI_CHAN_EEPROM1, value); // Send the value to be written
+  WRITE(SPI_EEPROM1_CS, HIGH);      // Done with the Bus
+  delay(EEPROM_WRITE_DELAY);        // Give page write time to complete
+}
+
+#endif // USE_SHARED_EEPROM
+#endif // I2C_EEPROM