added some sample code for menus

this is just an idea how menus could be done

modules/menutest.c

@@ -0,0 +1,140 @@
+#include <sysinit.h>
+
+#include "basic/basic.h"
+
+#include "lcd/render.h"
+#include "lcd/backlight.h"
+#include "lcd/allfonts.h"
+
+void ReinvokeISP(void);
+
+void incBacklight(void);
+void decBacklight(void);
+void gotoISP(void);
+
+void handleMenu(void);
+
+/**************************************************************************/
+
+struct MENU_DEF {
+    char *text;
+    void (*callback)(void);
+};
+
+typedef const struct MENU_DEF * menuentry;
+
+const struct MENU_DEF menu_incBL = {"Backlight++", &incBacklight};
+const struct MENU_DEF menu_decBL = {"Backlight--", &decBacklight};
+const struct MENU_DEF menu_ISP = {"Invoke ISP", &gotoISP};
+
+static menuentry menu[] = {
+    &menu_incBL,
+    &menu_decBL,
+    &menu_ISP,
+};
+
+void module_menutest(void) {
+
+    backlightInit();
+
+    font_direction = FONT_DIR_LTR; // LeftToRight is the default
+
+    while (1) {
+        lcdDisplay(0);
+        delayms(10);
+
+        lcdFill(0); // clear display buffer
+
+        font = &Font_Orbitron14pt;
+
+        DoString(0, 0, "Menü");
+
+        if (gpioGetValue(RB_BTN4)==0) {
+            while(gpioGetValue(RB_BTN4)==0);
+            handleMenu();
+        }
+    }
+
+    return;
+}
+
+void handleMenu(void) {
+    uint8_t back = 0;
+    uint8_t menuselection = 0;
+
+    font = &Font_7x8;
+
+    while (!back) {
+        uint8_t line = 0;
+        uint8_t col = 0;
+
+        lcdDisplay(0);
+        delayms(10);
+
+        lcdFill(0); // clear display buffer
+
+        DoString(0, line, "Menu");
+        line += font->u8Height;
+
+        if (gpioGetValue(RB_BTN1)==0) {
+            while(gpioGetValue(RB_BTN1)==0);
+            if (menuselection != 0) menuselection--;
+        }
+
+        if (gpioGetValue(RB_BTN0)==0) {
+            while(gpioGetValue(RB_BTN0)==0);
+            if (menuselection != 2)
+                menuselection++;
+            else
+                menuselection = 0; // wrap around
+        }
+
+        for (uint8_t i = 0; i < 3; i++) {
+            DoString(14, line + i*8, menu[i]->text);
+            if (i == menuselection) {
+                DoString(0, line + i*8, "* ");
+            }
+        }
+
+        if (gpioGetValue(RB_BTN4)==0) {
+            while(gpioGetValue(RB_BTN4)==0);
+            menu[menuselection]->callback();
+        }
+
+        if (gpioGetValue(RB_BTN2)==0) {
+            while(gpioGetValue(RB_BTN2)==0);
+            back = 1;
+        }
+
+        // fallback ISP via BTN3 ;)
+
+        if (gpioGetValue(RB_BTN3)==0) {
+            while(gpioGetValue(RB_BTN3)==0);
+            gotoISP();
+        }
+    }
+
+    return;
+}
+
+void incBacklight(void) {
+    uint32_t brightness = backlightGetBrightness();
+    if (brightness < 100) {
+        backlightSetBrightness(brightness + 10);
+    }
+}
+
+void decBacklight(void) {
+    uint32_t brightness = backlightGetBrightness();
+    if (brightness > 0) {
+        backlightSetBrightness(brightness - 10);
+    }
+}
+
+void gotoISP(void) {
+    DoString(0,58,"Enter ISP!");
+    lcdDisplay(0);
+    EnableWatchdog(5000);
+    ReinvokeISP();
+}
+