Improved bluetooth throughput from 50kBps to 60Bps

Updated camera FPS script to show FPS value

Author: siliconwitch

source/application/bluetooth.c

@@ -368,7 +368,7 @@ void bluetooth_setup(bool factory_reset)
     ble_cfg_t cfg;
     cfg.conn_cfg.conn_cfg_tag = 1;
     cfg.conn_cfg.params.gap_conn_cfg.conn_count = 1;
-    cfg.conn_cfg.params.gap_conn_cfg.event_length = 300;
+    cfg.conn_cfg.params.gap_conn_cfg.event_length = (15 * 1000) / 1250;
     check_error(sd_ble_cfg_set(BLE_CONN_CFG_GAP, &cfg, ram_start));
 
     // Set BLE role to peripheral only

source/application/bluetooth.h

@@ -28,7 +28,7 @@
 #include <stddef.h>
 #include <stdint.h>
 
-#define BLE_PREFERRED_MAX_MTU 256
+#define BLE_PREFERRED_MAX_MTU 185
 extern uint16_t ble_negotiated_mtu;
 
 void bluetooth_setup(bool factory_reset);

source/memory_layout.ld

@@ -51,7 +51,7 @@ ENTRY(Reset_Handler)
 MEMORY
 {
     APPLICATION_FLASH (rx) :      ORIGIN = 0x27000,    LENGTH = 0xCE000
-    APPLICATION_RAM (rwx) :       ORIGIN = 0x20002A08, LENGTH = 256K - 0x2A08
+    APPLICATION_RAM (rwx) :       ORIGIN = 0x200026F8, LENGTH = 256K - 0x26F8
 
     BOOTLOADER_FLASH (rx) :       ORIGIN = 0xF5000,    LENGTH = 0x9000
     BOOTLOADER_RAM (rwx) :        ORIGIN = 0x20002AE8, LENGTH = 256K - 0x2AE8

tests/test_camera_fps.py

@@ -1,6 +1,7 @@
 from aioconsole import ainput
 from frameutils import Bluetooth
 import asyncio
+import time
 
 header = bytearray(
     [
@@ -631,20 +632,26 @@
 )
 
 image_buffer = b""
+last_fps_time = time.time()
+fps = 0
 
 
 def receive_data(data):
     global image_buffer
+    global last_fps_time
+    global fps
 
     if len(data) == 1:
         with open("temp_focus_image.jpg", "wb") as f:
             f.write(header + image_buffer)
             image_buffer = b""
+            fps = 1 / (time.time() - last_fps_time)
+            last_fps_time = time.time()
         return
 
     image_buffer += data[1:]
     print(
-        f"Received {str(len(image_buffer)-1)} bytes. Press enter to finish      ",
+        f"Received {str(len(image_buffer)-1)} bytes. FPS = {fps}. Press enter to finish      ",
         end="\r",
     )
 
@@ -658,11 +665,11 @@ async def main():
 
     while true do
         if state == 'CAPTURE' then
-            frame.camera.capture { quality_factor = 25 }
+            frame.camera.capture { quality_factor = 50 }
             state_time = frame.time.utc()
             state = 'WAIT'
         elseif state == 'WAIT' then
-            if frame.time.utc() > state_time + 0.2 then
+            if frame.time.utc() > state_time + 0.1 then
                 state = 'SEND'
             end
         elseif state == 'SEND' then