Capacitive Touch Screen (GT911) for SKR SE BX (#21843)

Co-authored-by: Msq001 <alansayyeah@gmail.com>
Co-authored-by: Scott Lahteine <github@thinkyhead.com>

Marlin/src/HAL/STM32/tft/gt911.cpp

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+/**
+ * Marlin 3D Printer Firmware
+ * Copyright (c) 2021 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/>.
+ *
+ */
+#if defined(ARDUINO_ARCH_STM32) && !defined(STM32GENERIC)
+
+#include "../../../inc/MarlinConfig.h"
+
+#if ENABLED(TFT_TOUCH_DEVICE_GT911)
+
+#include "gt911.h"
+#include "pinconfig.h"
+
+SW_IIC::SW_IIC(uint16_t sda, uint16_t scl) {
+  scl_pin = scl;
+  sda_pin = sda;
+}
+
+// Software I2C hardware io init
+void SW_IIC::init() {
+  OUT_WRITE(scl_pin, HIGH);
+  OUT_WRITE(sda_pin, HIGH);
+}
+
+// Software I2C start signal
+void SW_IIC::start() {
+  write_sda(HIGH); // SDA = 1
+  write_scl(HIGH); // SCL = 1
+  iic_delay(2);
+  write_sda(LOW); // SDA = 0
+  iic_delay(1);
+  write_scl(LOW); // SCL = 0  // keep SCL low, avoid false stop caused by level jump caused by SDA switching IN/OUT
+}
+
+// Software I2C stop signal
+void SW_IIC::stop() {
+  write_scl(LOW); // SCL = 0
+  iic_delay(2);
+  write_sda(LOW); // SDA = 0
+  iic_delay(2);
+  write_scl(HIGH); // SCL = 1
+  iic_delay(2);
+  write_sda(HIGH); // SDA = 1
+}
+
+// Software I2C sends ACK or NACK signal
+void SW_IIC::send_ack(bool ack) {
+  write_sda(ack ? LOW : HIGH); // SDA = !ack
+  iic_delay(2);
+  write_scl(HIGH); // SCL = 1
+  iic_delay(2);
+  write_scl(LOW); // SCL = 0
+}
+
+// Software I2C read ACK or NACK signal
+bool SW_IIC::read_ack() {
+  bool error = 0;
+  set_sda_in();
+
+  iic_delay(2);
+
+  write_scl(HIGH); // SCL = 1
+  error = read_sda();
+
+  iic_delay(2);
+
+  write_scl(LOW);  // SCL = 0
+
+  set_sda_out();
+  return error;
+}
+
+void SW_IIC::send_byte(uint8_t txd) {
+  LOOP_L_N(i, 8) {
+    write_sda(txd & 0x80); // write data bit
+    txd <<= 1;
+    iic_delay(1);
+    write_scl(HIGH); // SCL = 1
+    iic_delay(2);
+    write_scl(LOW); // SCL = 0
+    iic_delay(1);
+  }
+
+  read_ack();  // wait ack
+}
+
+uint8_t SW_IIC::read_byte(bool ack) {
+  uint8_t data = 0;
+
+  set_sda_in();
+  LOOP_L_N(i, 8) {
+    write_scl(HIGH); // SCL = 1
+    iic_delay(1);
+    data <<= 1;
+    if (read_sda()) data++;
+    write_scl(LOW); // SCL = 0
+    iic_delay(2);
+  }
+  set_sda_out();
+
+  send_ack(ack);
+
+  return data;
+}
+
+GT911_REG_MAP GT911::reg;
+SW_IIC GT911::sw_iic = SW_IIC(GT911_SW_I2C_SDA_PIN, GT911_SW_I2C_SCL_PIN);
+
+void GT911::write_reg(uint16_t reg, uint8_t reg_len, uint8_t* w_data, uint8_t w_len) {
+  sw_iic.start();
+  sw_iic.send_byte(gt911_slave_address);  // Set IIC Slave address
+  LOOP_L_N(i, reg_len) {  // Set reg address
+    uint8_t r = (reg >> (8 * (reg_len - 1 - i))) & 0xFF;
+    sw_iic.send_byte(r);
+  }
+
+  LOOP_L_N(i, w_len) {  // Write data to reg
+    sw_iic.send_byte(w_data[i]);
+  }
+  sw_iic.stop();
+}
+
+void GT911::read_reg(uint16_t reg, uint8_t reg_len, uint8_t* r_data, uint8_t r_len) {
+  sw_iic.start();
+  sw_iic.send_byte(gt911_slave_address);  // Set IIC Slave address
+  LOOP_L_N(i, reg_len) {  // Set reg address
+    uint8_t r = (reg >> (8 * (reg_len - 1 - i))) & 0xFF;
+    sw_iic.send_byte(r);
+  }
+
+  sw_iic.start();
+  sw_iic.send_byte(gt911_slave_address + 1);  // Set read mode
+
+  LOOP_L_N(i, r_len) {
+    r_data[i] = sw_iic.read_byte(1);  // Read data from reg
+  }
+  sw_iic.stop();
+}
+
+void GT911::Init() {
+  OUT_WRITE(GT911_RST_PIN, LOW);
+  OUT_WRITE(GT911_INT_PIN, LOW);
+  delay(20);
+  WRITE(GT911_RST_PIN, HIGH);
+  SET_INPUT(GT911_INT_PIN);
+
+  sw_iic.init();
+
+  uint8_t clear_reg = 0x0000;
+  write_reg(0x814E, 2, &clear_reg, 2); // Reset to 0 for start
+}
+
+bool GT911::getFirstTouchPoint(int16_t *x, int16_t *y) {
+  read_reg(0x814E, 2, &reg.REG.status, 1);
+
+  if (reg.REG.status & 0x80) {
+    uint8_t clear_reg = 0x00;
+    write_reg(0x814E, 2, &clear_reg, 1); // Reset to 0 for start
+    read_reg(0x8150, 2, reg.map + 2, 8 * (reg.REG.status & 0x0F));
+
+    // First touch point
+    *x = ((reg.REG.point[0].xh & 0x0F) << 8) | reg.REG.point[0].xl;
+    *y = ((reg.REG.point[0].yh & 0x0F) << 8) | reg.REG.point[0].yl;
+    return true;
+  }
+  return false;
+}
+
+bool GT911::getPoint(int16_t *x, int16_t *y) {
+  static bool touched = 0;
+  static int16_t read_x = 0, read_y = 0;
+  static millis_t next_time = 0;
+
+  if (ELAPSED(millis(), next_time)) {
+    touched = getFirstTouchPoint(&read_x, &read_y);
+    next_time = millis() + 20;
+  }
+
+  *x = read_x;
+  *y = read_y;
+  return touched;
+}
+
+#endif // TFT_TOUCH_DEVICE_GT911
+#endif // ARDUINO_ARCH_STM32 && !STM32GENERIC