stm32: Use shared poll interval define and enable DLE.

Use ZEPHYR_BLE_POLL_INTERVAL_MS for poll timer values.
Enable CONFIG_BT_AUTO_DATA_LEN_UPDATE for NUCLEO_WB55.

Signed-off-by: Andrew Leech <andrew.leech@planetinnovation.com.au>

Author: pi-anl

ports/stm32/boards/NUCLEO_WB55/mpconfigvariant_zephyr_ble.mk

@@ -13,5 +13,8 @@ MICROPY_HW_ENABLE_ISR_UART_FLASH_FUNCS_IN_RAM = 0
 # Use bump allocator for GATT structures (STM32 Zephyr builds don't link libc)
 CFLAGS += -DMICROPY_BLUETOOTH_ZEPHYR_GATT_POOL=1
 
+# Enable auto DLE — STM32WB controller handles DLE fine
+CFLAGS += -DCONFIG_BT_AUTO_DATA_LEN_UPDATE=1
+
 # Force linker to keep HCI device symbols (prevent --gc-sections from removing them)
 LDFLAGS += -Wl,--undefined=__device_dts_ord_0 -Wl,--undefined=mp_bluetooth_zephyr_hci_dev

ports/stm32/mpconfigport.h

@@ -237,7 +237,7 @@ typedef long mp_off_t;
         __WFI(); \
     } while (0);
 
-#define MICROPY_THREAD_YIELD()
+// MICROPY_THREAD_YIELD defined in mphalport.h (upstream).
 
 // Configuration for shared/runtime/softtimer.c.
 #define MICROPY_SOFT_TIMER_TICKS_MS uwTick

ports/stm32/mpzephyrport.c

@@ -307,7 +307,7 @@ static int hci_stm32_open(const struct device *dev, bt_hci_recv_t recv) {
 
     // Start the soft timer to begin periodic work queue processing
     // This starts the timer which will fire and process work queues + HCI packets
-    mp_bluetooth_zephyr_port_poll_in_ms(128);  // Start timer with 128ms delay
+    mp_bluetooth_zephyr_port_poll_in_ms(ZEPHYR_BLE_POLL_INTERVAL_MS);
 
     return 0;
 }
@@ -498,7 +498,7 @@ void mp_bluetooth_hci_poll(void) {
     mp_bluetooth_zephyr_port_run_task(NULL);
 
     // Schedule next poll if stack is active
-    mp_bluetooth_zephyr_port_poll_in_ms(128);
+    mp_bluetooth_zephyr_port_poll_in_ms(ZEPHYR_BLE_POLL_INTERVAL_MS);
 }
 
 // Initialize Zephyr port (called early in initialization)