Direct sampling: brand new implementation.

view_direct_sampling.c

@@ -2,10 +2,13 @@
  * See the LICENSE file for information about the license. */
 
 #include "app.h"
-
 #include <cc1101.h>
 
-#define CAPTURED_BITMAP_SIZE 128*64/8
+static void direct_sampling_timer_start(ProtoViewApp *app);
+static void direct_sampling_timer_stop(ProtoViewApp *app);
+
+#define CAPTURED_BITMAP_BITS (128*64)
+#define CAPTURED_BITMAP_BYTES (CAPTURED_BITMAP_BITS/8)
 #define DEFAULT_USEC_PER_PIXEL 50
 #define USEC_PER_PIXEL_SMALL_CHANGE 5
 #define USEC_PER_PIXEL_LARGE_CHANGE 25
@@ -13,7 +16,9 @@
 #define USEC_PER_PIXEL_MAX 300
 typedef struct {
     uint8_t *captured; // Bitmap with the last captured screen.
+    uint32_t captured_idx;   // Current index to write into the bitmap
     uint32_t usec_per_pixel; // Number of useconds a pixel should represent
+    bool show_usage_info;
 } DirectSamplingViewPrivData;
 
 /* Read directly from the G0 CC1101 pin, and draw a black or white
@@ -21,41 +26,25 @@ typedef struct {
 void render_view_direct_sampling(Canvas *const canvas, ProtoViewApp *app) {
     DirectSamplingViewPrivData *privdata = app->view_privdata;
 
-    if (!app->direct_sampling_enabled && privdata->captured == NULL) {
+    if (!app->direct_sampling_enabled && privdata->show_usage_info) {
         canvas_set_font(canvas, FontSecondary);
-        canvas_draw_str(canvas,2,9,"Direct sampling is a special");
-        canvas_draw_str(canvas,2,18,"mode that displays the signal");
-        canvas_draw_str(canvas,2,27,"captured in real time. Like in");
-        canvas_draw_str(canvas,2,36,"a old CRT TV. It's very slow.");
-        canvas_draw_str(canvas,2,45,"Can crash your Flipper.");
+        canvas_draw_str(canvas,2,9, "Direct sampling displays the");
+        canvas_draw_str(canvas,2,18,"the captured signal in real");
+        canvas_draw_str(canvas,2,27,"time, like in a CRT TV set.");
+        canvas_draw_str(canvas,2,36,"Use UP/DOWN to change the");
+        canvas_draw_str(canvas,2,45,"resolution (usec/pixel).");
         canvas_set_font(canvas, FontPrimary);
-        canvas_draw_str(canvas,14,60,"To enable press OK");
+        canvas_draw_str(canvas,5,60,"To start/stop, press OK");
         return;
     }
-
-    /* Allocate the bitmap only the first time. */
-    if (privdata->captured == NULL)
-        privdata->captured = malloc(CAPTURED_BITMAP_SIZE);
-
-    /* Read from data from GPIO */
-    if (app->direct_sampling_enabled) {
-        for (int j = 0; j < CAPTURED_BITMAP_SIZE*8; j++) {
-            uint32_t start_time = DWT->CYCCNT;
-            bool level = furi_hal_gpio_read(&gpio_cc1101_g0);
-            bitmap_set(privdata->captured,CAPTURED_BITMAP_SIZE,j,level);
-            uint32_t period =
-                furi_hal_cortex_instructions_per_microsecond() *
-                privdata->usec_per_pixel;
-            while(DWT->CYCCNT - start_time < period);
-        }
-    }
+    privdata->show_usage_info = false;
 
     /* Draw on screen. */
     int idx = 0;
     for (int y = 0; y < 64; y++) {
         for (int x = 0; x < 128; x++) {
             bool level = bitmap_get(privdata->captured,
-                CAPTURED_BITMAP_SIZE,idx++);
+                CAPTURED_BITMAP_BYTES,idx++);
             if (level) canvas_draw_dot(canvas,x,y);
         }
     }
@@ -63,7 +52,7 @@ void render_view_direct_sampling(Canvas *const canvas, ProtoViewApp *app) {
     char buf[32];
     snprintf(buf,sizeof(buf),"%lu usec/px", privdata->usec_per_pixel);
     canvas_set_font(canvas, FontSecondary);
-    canvas_draw_str_with_border(canvas,0,60,buf,ColorWhite,ColorBlack);
+    canvas_draw_str_with_border(canvas,1,60,buf,ColorWhite,ColorBlack);
 }
 
 /* Handle input */
@@ -86,6 +75,9 @@ void process_input_direct_sampling(ProtoViewApp *app, InputEvent input) {
             privdata->usec_per_pixel = USEC_PER_PIXEL_MIN;
         else if (privdata->usec_per_pixel > USEC_PER_PIXEL_MAX)
             privdata->usec_per_pixel = USEC_PER_PIXEL_MAX;
+        /* Update the timer frequency. */
+        direct_sampling_timer_stop(app);
+        direct_sampling_timer_start(app);
     }
 }
 
@@ -95,6 +87,8 @@ void view_enter_direct_sampling(ProtoViewApp *app) {
     /* Set view defaults. */
     DirectSamplingViewPrivData *privdata = app->view_privdata;
     privdata->usec_per_pixel = DEFAULT_USEC_PER_PIXEL;
+    privdata->captured = malloc(CAPTURED_BITMAP_BYTES);
+    privdata->show_usage_info = true;
 
     if (app->txrx->txrx_state == TxRxStateRx &&
         !app->txrx->debug_timer_sampling)
@@ -111,6 +105,9 @@ void view_enter_direct_sampling(ProtoViewApp *app) {
     } else {
         raw_sampling_worker_stop(app);
     }
+
+    // Start the timer to capture raw data
+    direct_sampling_timer_start(app);
 }
 
 /* Exit view. Restore the subghz thread. */
@@ -119,6 +116,8 @@ void view_exit_direct_sampling(ProtoViewApp *app) {
     if (privdata->captured) free(privdata->captured);
     app->direct_sampling_enabled = false;
 
+    direct_sampling_timer_stop(app);
+
     /* Restart normal data feeding. */
     if (app->txrx->txrx_state == TxRxStateRx &&
         !app->txrx->debug_timer_sampling)
@@ -128,3 +127,47 @@ void view_exit_direct_sampling(ProtoViewApp *app) {
         raw_sampling_worker_start(app);
     }
 }
+
+/* =========================== Timer implementation ========================= */
+
+static void ds_timer_isr(void *ctx) {
+    ProtoViewApp *app = ctx;
+    DirectSamplingViewPrivData *privdata = app->view_privdata;
+
+    if (app->direct_sampling_enabled) {
+        bool level = furi_hal_gpio_read(&gpio_cc1101_g0);
+        bitmap_set(privdata->captured,CAPTURED_BITMAP_BYTES,
+                   privdata->captured_idx,level);
+        privdata->captured_idx = (privdata->captured_idx+1) %
+                                 CAPTURED_BITMAP_BITS;
+    }
+    LL_TIM_ClearFlag_UPDATE(TIM2);
+}
+
+static void direct_sampling_timer_start(ProtoViewApp *app) {
+    DirectSamplingViewPrivData *privdata = app->view_privdata;
+
+    LL_TIM_InitTypeDef tim_init = {
+        .Prescaler = 63,    /* CPU frequency is ~64Mhz. */
+        .CounterMode = LL_TIM_COUNTERMODE_UP,
+        .Autoreload = privdata->usec_per_pixel
+    };
+
+    LL_TIM_Init(TIM2, &tim_init);
+    LL_TIM_SetClockSource(TIM2, LL_TIM_CLOCKSOURCE_INTERNAL);
+    LL_TIM_DisableCounter(TIM2);
+    LL_TIM_SetCounter(TIM2, 0);
+    furi_hal_interrupt_set_isr(FuriHalInterruptIdTIM2, ds_timer_isr, app);
+    LL_TIM_EnableIT_UPDATE(TIM2);
+    LL_TIM_EnableCounter(TIM2);
+}
+
+static void direct_sampling_timer_stop(ProtoViewApp *app) {
+    UNUSED(app);
+    FURI_CRITICAL_ENTER();
+    LL_TIM_DisableCounter(TIM2);
+    LL_TIM_DisableIT_UPDATE(TIM2);
+    furi_hal_interrupt_set_isr(FuriHalInterruptIdTIM2, NULL, NULL);
+    LL_TIM_DeInit(TIM2);
+    FURI_CRITICAL_EXIT();
+}