DFR0492

      FireBeetle Board‐328P with BLE4.1 SKU: DFR0492      Introduction DFRobot FireBeetle series are low power consumption controllers designed for Internet of Things (IoT) development. This Bluetooth controller combines Bluetooth Low Energy 4.1 with Arduino controller, offering functions similar to the former Bluno series but with lower power consumption. FireBeetle BLE 4.1 is compatible with Bluno series (BLE 4.0) and performs much better. It equipped with more stable DIALOG Bluetooth 4.1 chip, supporting maximum 4Kbyte/s transmission rate and low power consumption (25uA POWER DOWN). It can be directly applied to low power consumption application such as wearable and intelligent tools and so on. It also supports multiple Bluetooth cascade, KISS connection(approach connection) and compatible with Bluno series. Its connection can be realized by holding host BOOT and moving to the target peripheral device.   Features              Support Arduino IDE program Support BLE 4.1 central and peripheral switch Support Bluetooth serial port data transmit Support Bluetooth peer to peer (P2P) wireless programming Support Bluetooth 4.1 multiple device cascade (maximum:4) Support Arduino Bluetooth library (support multiple Bluetooth connection) Support low power consumption Bluetooth (standby current: 25uA; enabled interrupt current: 70uA) Double interruption to wake up: BLE4.1 awake Atmage328P by D2 (high level awake) Atmage328P awake BLE4.1 by D3 (low level awake) Support KISS connection(approach connection) Support Bluetooth firmware update Support USB charge Support lithium battery power supply Equipped with status LEDs Specification                  Processor: ATMEGA328P Bootloader: Arduino Pro or Pro Mini, ATmega328 (3.3V, 8MHz) Operating Current: 3.3V VCC I/O Voltage: 3.7V~5.5V Lithium Battery Voltage: 3.7V Support maximum 4Kbyte/s transmission rate (more device, lower rate) Support low power consumption: 25uA (POWER DOWN); 70uA (enabled interruption) Support maximum discharge current: 600mA (LDO-3.3V OUTPUT) Support maximum charge current: 400Ma Digital Interfaces: 14 Analog Interfaces: 6 SPI: 1 I2C: 1 UART: 1 LED_BUILTIN: D13 Interface Mode: 2.54mm (Pin/Female header), soldering free in default Dimension: 58 * 29 mm/ 2.28 * 1.14 inches Board Overview Fig1: FireBeetle Board-328P with BLE4.1 PinOUT LED indicators     RX: Serial data receiving indicator, light up when receive serial data TX: Serial data transmitting indicator, light up when send serial data CHG: Battery charge indicator: Flash without lithium battery; Light ON in charging; Light OFF when full charged LINK: a Bluetooth connect indicator; when Bluetooth connect to the device successfully, LINK will light for 3s and blink for every 3s, light OFF when disconnected. Buttons   BOOT: Bluetooth firmware update; enable KISS connection (approach connection). Firmware update: please press and hold BOOT button and power-up (plug in USB), turning to the firmware update mode. For any enquiries, please refers to the part: Firmware Update. Approach connection: please hold the central BOOT button when it is in the working mode, approaching the peripheral Bluetooth device and connect. RST Arduino Reset button Note: VCC is the output voltage of the power supply (USB power supply: 5V, lithium battery power supply: 3.7V) Arduino Tutorial Choose a suitable Arduino board Considering low power consumption, we select Arduino Pro Mini @3.3V 8MHz as Bootloader for FireBeetle BLE4.1 microcontrollers. Fig2: FireBeetle Board-328P with BLE4.1 Special Note: Pro Mini uses 8MHz OCXO. Its processing speed is relatively slow for 115200-baud rate. The high baud rate may lead to unreadable code and packet loss etc. 9600-baud rate is recommended. Low Power Consumption Mode BLE 4.1 switch to low power consumption mode with AT command: AT+LOWPOWER=ON. The Bluetooth can still broadcast and connect in the low power mode. When the Bluetooth received data, it will awake automatically and send an interrupt signal to the chip: 328p. The interrupt pin here should be connected to D2 of 328p which is interrupt 0 in the code. void wakeup(){ sleep_disable(); delay(2000); } void lowpower(){ ADCSRA &= ~(1