prefetch volcano ble characteristics

README.md

 # Pi Pico Volcano Remote Control Gadget
 
+Supports:
+
+ * workflows for the Volcano Hybrid
+ * basic status and settings for Crafty+
+
 For use with Raspberry Pi Pico W boards with the [Waveshare Pico LCD 1.3](https://www.waveshare.com/wiki/Pico-LCD-1.3) and the [Pimoroni Pico Lipo Shim](https://shop.pimoroni.com/products/pico-lipo-shim).
 
 Adapted from the [tinyusb-cdc-example](https://github.com/hathach/tinyusb/blob/master/examples/device/cdc_msc/src/main.c), [adc example](https://github.com/raspberrypi/pico-examples/tree/master/adc/read_vsys), [standalone client example](https://github.com/raspberrypi/pico-examples/blob/master/pico_w/bt/standalone/client.c) and my [Trackball firmware](https://git.xythobuz.de/thomas/Trackball).
 
+`python-test` contains a similar app to the C version in the top level of the repo, but instead written for MicroPython on the Pico W.
+Unfortunately I had many performance and space problems with this, so I decided to rewrite it.
+`web-app` contains a script to conveniently fetch the original web app JS sources, for "reverse engineering".
+
 ## Quick Start
 
 When compiling for the first time, check out the required git submodules.

include/ble.h

 bool ble_is_connected(void);
 void ble_disconnect(void);
 
+int8_t ble_discover(const uint8_t *service, const uint8_t *characteristic);
+
 int32_t ble_read(const uint8_t *characteristic, uint8_t *buff, uint16_t buff_len);
 int8_t ble_write(const uint8_t *service, const uint8_t *characteristic,
-                 uint8_t *buff, uint16_t buff_len);
+                 const uint8_t *buff, uint16_t buff_len);
 
 #endif // __BLE_H__

include/volcano.h

 #include <stdint.h>
 #include <stdbool.h>
 
+// returns < 0 on error
+int8_t volcano_discover_characteristics(void);
+
 // in 1/10th degrees C, or < 0 on error
 int16_t volcano_get_current_temp(void);
 int16_t volcano_get_target_temp(void);

src/ble.c

 #include "util.h"
 #include "ble.h"
 
-#define BLE_READ_TIMEOUT_MS (2 * 500)
-#define BLE_SRVC_TIMEOUT_MS (2 * 500)
-#define BLE_CHAR_TIMEOUT_MS (2 * 2000)
-#define BLE_WRTE_TIMEOUT_MS (2 * 500)
+#define BLE_READ_TIMEOUT_MS (3 * 500)
+#define BLE_SRVC_TIMEOUT_MS (3 * 500)
+#define BLE_CHAR_TIMEOUT_MS (3 * 2000)
+#define BLE_WRTE_TIMEOUT_MS (3 * 500)
 #define BLE_MAX_SCAN_AGE_MS (10 * 1000)
 #define BLE_MAX_SERVICES 8
 #define BLE_MAX_CHARACTERISTICS 8
     return read_len;
 }
 
-int8_t ble_write(const uint8_t *service, const uint8_t *characteristic,
-                  uint8_t *buff, uint16_t buff_len) {
-    cyw43_thread_enter();
-
-    if (state != TC_READY) {
-        cyw43_thread_exit();
-        debug("invalid state for write (%d)", state);
-        return -1;
-    }
-
+static int discover_service(const uint8_t *service) {
     // check if service has already been discovered
     int srvc = -1, free_srvc = -1;
     for (int i = 0; i < BLE_MAX_SERVICES; i++) {
         cyw43_thread_enter();
     }
 
+    return srvc;
+}
+
+static int discover_characteristic(int srvc, const uint8_t *characteristic) {
     // check if characteristic has already been discovered
     int ch = -1, free_ch = -1;
     for (int i = 0; i < BLE_MAX_CHARACTERISTICS; i++) {
         cyw43_thread_enter();
     }
 
+    return ch;
+}
+
+int8_t ble_write(const uint8_t *service, const uint8_t *characteristic,
+                 const uint8_t *buff, uint16_t buff_len) {
+    cyw43_thread_enter();
+
+    if (state != TC_READY) {
+        cyw43_thread_exit();
+        debug("invalid state for write (%d)", state);
+        return -1;
+    }
+
+    int srvc = discover_service(service);
+    if (srvc < 0) {
+        debug("error discovering service (%d)", srvc);
+        return srvc;
+    }
+
+    int ch = discover_characteristic(srvc, characteristic);
+    if (ch < 0) {
+        debug("error discovering characteristic (%d)", ch);
+        return ch;
+    }
+
     if (buff_len > BLE_MAX_VALUE_LEN) {
         buff_len = BLE_MAX_VALUE_LEN;
     }
     cyw43_thread_exit();
     return ret;
 }
+
+int8_t ble_discover(const uint8_t *service, const uint8_t *characteristic) {
+    cyw43_thread_enter();
+
+    if (state != TC_READY) {
+        cyw43_thread_exit();
+        debug("invalid state for discovery (%d)", state);
+        return -1;
+    }
+
+    int srvc = discover_service(service);
+    if (srvc < 0) {
+        debug("error discovering service (%d)", srvc);
+        return srvc;
+    }
+
+    int ch = discover_characteristic(srvc, characteristic);
+    if (ch < 0) {
+        debug("error discovering characteristic (%d)", ch);
+        return ch;
+    }
+
+    cyw43_thread_exit();
+    return 0;
+}

src/state_crafty.c

 
 #include "menu.h"
 
-#define CRAFTY_UPDATE_TIME_MS 1000
+#define CRAFTY_UPDATE_TIME_MS 3000
 
 static bd_addr_t ble_addr = {0};
 static bd_addr_type_t ble_type = 0;
     static uint32_t last = 0;
     uint32_t now = to_ms_since_boot(get_absolute_time());
     if (((now - last) >= CRAFTY_UPDATE_TIME_MS) || (last == 0)) {
-        last = now;
         menu_run(draw, true);
+        last = to_ms_since_boot(get_absolute_time());
     }
 
     if (wait_for_disconnect && !ble_is_connected()) {

src/volcano.c

     0x5a, 0x26, 0x42, 0x49, 0x43, 0x4b, 0x45, 0x4c,
 };
 
+int8_t volcano_discover_characteristics(void) {
+    uuid_base[3] = UUID_WRITE_SRVC;
+    int8_t r;
+
+    uuid_base2[3] = UUID_TARGET_TEMP;
+    r = ble_discover(uuid_base, uuid_base2);
+    if (r < 0) {
+        return r;
+    }
+
+    uuid_base2[3] = UUID_HEATER_ON;
+    r = ble_discover(uuid_base, uuid_base2);
+    if (r < 0) {
+        return r;
+    }
+
+    uuid_base2[3] = UUID_HEATER_OFF;
+    r = ble_discover(uuid_base, uuid_base2);
+    if (r < 0) {
+        return r;
+    }
+
+    uuid_base2[3] = UUID_PUMP_ON;
+    r = ble_discover(uuid_base, uuid_base2);
+    if (r < 0) {
+        return r;
+    }
+
+    uuid_base2[3] = UUID_PUMP_OFF;
+    r = ble_discover(uuid_base, uuid_base2);
+    if (r < 0) {
+        return r;
+    }
+
+    return 0;
+}
+
 int16_t volcano_get_current_temp(void) {
     uuid_base[3] = UUID_CURRENT_TEMP;
 

src/workflow.c

     wf_i = index;
     step = 0;
 
-    // discover characteristics
-    volcano_set_pump_state(false);
-    volcano_set_heater_state(false);
-    volcano_set_target_temp(1850);
-
+    /*
+     * first turn on heater, then do discovery, to save some time.
+     * this means we heat for some seconds before changing the setpoint.
+     * should not be a problem in practice.
+     */
     volcano_set_heater_state(true);
+    volcano_discover_characteristics();
 
     do_step();
 }