Add support for touch controller of LCD

CMakeLists.txt

@@ -43,10 +43,10 @@ target_link_libraries(ledtest pico_stdlib hardware_pio)
 pico_add_extra_outputs(ledtest)
 
 add_executable(lcdtest
-  src/lcdtest.c src/lcdbus.c src/lcd_ui.c src/ui_radio.c
+  src/lcdtest.c src/lcdbus.c src/lcd_ui.c src/ui_radio.c src/touch.c
 )
 
 pico_generate_pio_header(lcdtest ${CMAKE_CURRENT_LIST_DIR}/src/lcdbus.pio)
-target_link_libraries(lcdtest pico_stdlib hardware_pio)
+target_link_libraries(lcdtest pico_stdlib hardware_pio hardware_spi)
 pico_add_extra_outputs(lcdtest)
 

src/lcdtest.c

@@ -3,6 +3,7 @@
 #include "lcdbus.h"
 #include "lcd_ui.h"
 #include "ui_radio.h"
+#include "touch.h"
 #include <pico/stdlib.h>
 #include <stdio.h>
 
@@ -18,6 +19,8 @@ int main(void)
     lcd_init();
     lcd_write_init();
     lcd_clear(0);
+
+    touch_init();
    
     gpio_init(FRAME_LED);
     gpio_set_dir(FRAME_LED, true);
@@ -25,15 +28,41 @@ int main(void)
     int freq = 118000;
     unsigned last_inc = time_us_32()/1000;
     radio_draw_all();
-    radio_select_input(&radio_vhf1, true);
+    struct radio_ui *active_radio = NULL;
+    unsigned touch_stable_time = 0;
+    int last_hit_x = -1, last_hit_y = -1;
     while(true) {
 	if (lcd_ui_process(false)) {
 	    gpio_put(FRAME_LED, frame_led);
 	    frame_led = !frame_led;
 	}
+	unsigned hit_x, hit_y;
+	if (touch_query(2, 4, &hit_x, &hit_y)) {
+	  struct radio_ui *touched_radio = NULL;
+	  if (hit_x == 0 && hit_y == 0)
+	    touched_radio = &radio_vhf1;
+	  else if (hit_x == 1 && hit_y == 0)
+	    touched_radio = &radio_vhf2;
+	  else if (hit_x == 0 && hit_y == 1)
+	    touched_radio = &radio_ils1;
+	  else if (hit_x == 1 && hit_y == 1)
+	    touched_radio = &radio_ils2;
+
+	  if (touched_radio != active_radio) {
+	    if (active_radio) {
+	      radio_select_input(active_radio, false);
+	    }
+	    if (touched_radio) {
+	      radio_select_input(touched_radio, true);
+	    }
+	    active_radio = touched_radio;
+	  }
+	}
 	if (time_us_32()/1000 - last_inc >= 1000) {
-	  radio_set_standby_freq(&radio_vhf1, freq);
-	  freq += 25;
+	  if (active_radio) {
+	    radio_set_standby_freq(active_radio, freq);
+	    freq += 25;
+	  }
 	  last_inc += 1000;
 	}
     }

src/touch.c

@@ -0,0 +1,65 @@
+#include "touch.h"
+
+#include <hardware/spi.h>
+#include <pico/stdlib.h>
+
+#define TOUCH_UPPER 3800
+#define TOUCH_LOWER 300
+#define TOUCH_LEFT  300
+#define TOUCH_RIGHT 3800
+
+void touch_init(void)
+{
+    spi_init(spi0, 1000000);
+    spi_set_format(spi0, 8, SPI_CPHA_0, SPI_CPOL_0, SPI_MSB_FIRST);
+    gpio_set_function(2, GPIO_FUNC_SPI);
+    gpio_set_function(3, GPIO_FUNC_SPI);
+    gpio_set_function(4, GPIO_FUNC_SPI);
+    gpio_set_function(5, GPIO_FUNC_SIO);
+    gpio_set_dir(5, true);
+    gpio_put(5, true);
+}
+
+static bool ads7843_xfer(uint16_t *const touch_x, uint16_t *const touch_y)
+{
+    const char outbuf_x[3] = {0xd0, 0x00, 0x00};
+    const char outbuf_y[3] = {0x90, 0x00, 0x00};
+    char inbuf[3];
+    gpio_put(5, false);
+    spi_write_read_blocking(spi0, outbuf_x, inbuf, 3);
+    gpio_put(5, true);
+    const uint16_t x = ((inbuf[1] & 0x7f) << 5) | ((inbuf[2] & 0xf8) >> 3);
+    gpio_put(5, false);
+    spi_write_read_blocking(spi0, outbuf_y, inbuf, 3);
+    gpio_put(5, true);
+    const uint16_t y = ((inbuf[1] & 0x7f) << 5) | ((inbuf[2] & 0xf8) >> 3);
+    //printf("X: %hu Y: %hu\n", x, y);
+    *touch_x = x;
+    *touch_y = y;
+    return (x > TOUCH_LEFT) && (x < TOUCH_RIGHT) && (y > TOUCH_LOWER) && (y < TOUCH_UPPER);
+}
+
+bool touch_query(unsigned x_boxes, unsigned y_boxes, unsigned *const x, unsigned *const y)
+{
+    static unsigned touch_stable_time = 0;
+    static int last_hit_x = -1, last_hit_y = -1;
+    uint16_t touch_x, touch_y;
+    if (ads7843_xfer(&touch_x, &touch_y)) {
+	const int hit_x = x_boxes * (touch_x - TOUCH_LEFT) / (TOUCH_RIGHT - TOUCH_LEFT);
+	const int hit_y = (y_boxes - 1) - y_boxes * (touch_y - TOUCH_LOWER) / (TOUCH_UPPER - TOUCH_LOWER);
+	if (hit_x != last_hit_x || hit_y != last_hit_y) {
+	    last_hit_x = hit_x;
+	    last_hit_y = hit_y;
+	    touch_stable_time = time_us_32();
+	}
+    } else {
+	last_hit_x = -1;
+	last_hit_y = -1;
+    }
+    if (last_hit_x >= 0 && last_hit_y >= 0 && time_us_32() - touch_stable_time >= 50000) {
+	*x = last_hit_x;
+	*y = last_hit_y;
+	return true;
+    }
+    return false;
+}

src/touch.h

@@ -0,0 +1,7 @@
+#pragma once
+
+#include <stdbool.h>
+#include <stdint.h>
+
+void touch_init(void);
+bool touch_query(unsigned x_boxes, unsigned y_boxes, unsigned *const x, unsigned *const y);