What is 4G A7672S?
The A7672S LTE Cat 1 module supports GSM/GPRS/EDGE LTE-FDD as well as other wireless connection modes. It features a maximum downlink speed of 10Mbps and a 5Mbps uplink speed.
It also comes along with a variety of pre-installed network protocols and drivers for popular operating systems (USB driver for Windows, Linux, and Android). The SIM800 series modules are compatible with AT commands in software. The A7672S also supports BLE* and GNSS*.
What makes it better than the other 4G modules?
The A7672S is a little device having a number of different interfaces. BLE and GNSS functionality, as well as several software capabilities including FOTA, LBS, and SSL, are all supported. The SIM7000/SIM7070 series form factor is compatible. Three power supply pins (55, 56, and 57) are provided as VBAT power input pins. The A7672X's internal RF and baseband circuitry are powered by these three pins. When the module is operating in GSM TX mode at full power, the peak current can reach 2A (peak current), causing a substantial voltage drop on Vbat . The external power source must have a power supply capability of at least 2A to ensure that the voltage drop is less than 300mV.
The module's RF performance will degrade if the voltage falls below 3.4V; if the voltage drops too low, the module will shut down. An LDO or DC-DC chip with an enable pin controlled by the MCU is recommended. The module must be turned off by the MCU, but it cannot usually be turned back on. It can only be switched off if the module is abnormal and cannot be shut down or restarted on a regular basis. When the voltage input is higher than 9V, the DCDC chip is recommended. When the input voltage is less than 9V, an LDO power supply is recommended. As there is no MCU, you can install a low-cost single-chip microcomputer to serve the hardware watchdog to pull POWERKEY to boot and shut off if you use the module's OPEN LINUX feature of secondary development. It is told to use a linear regulator power supply or a switching mode.
By pressing the reset pin on the module, the A7672S can restart it. The reset pin turns on when the PMU receives an adequate supply voltage for the first time (active low, but this key has no shutdown function). After the initial power-on, several registers of this pin will be written, and it will lose its function; therefore, it is recommended to use PWRKEY to turn on the module and RESET to reset it.
The A7672S features a USB interface that is compliant with the USB2.0 specification as a peripheral, but it does not support USB charging or USB HOST mode. USB is the primary debugging and software update mechanism. During the design phase, customers are urged to set aside USB test points. The A7672S module has an inbuilt Bluetooth capability, and the module interface only has one BT antenna. The A7672S supports only Bluetooth data transmission and does not offer VoiceOverPCM or VoHCI. It implements the Bluetooth 5.0 protocol specification and is compatible with both BLE low power mode and conventional Bluetooth mode.
The SPI LCD interfaces on the A7672S module only support LCD modules with one data line. The LCD TE signal pin is missing from the module's LCD interface. If necessary, you can use GPIO to simulate the use of the LCD TE signal. It is recommended that the LCD TE signal be transmitted through module pin 44. (MK OUT 2).
It is recommended that a decoupling capacitor and 0 resistors in series be set aside on the power supply for LCD debugging. Simultaneously, the data line has a 0 in series reserved to simplify signal quality control and prevent signal reflection and overshoot. The A7672s modules, which include an audio codec and an audio front end and provide 1 channel of the analogue audio MIC input interface and 1 channel of analogue audio SPK output interface, allow customers to connect to the external phone handle.
How A7672S interfacing with Nuvoton Microcontroller:-
On the same frequency, two UART devices receive and send data at the same time. When a start bit is detected by the receiving UART device, it starts reading the incoming bits at a particular frequency known as the baud rate. Because it measures the speed of data transfer in bits per second, the baud rate is crucial for UART connection (bps). Both the transmit and receive baud rates must be the same. Before bit timing becomes incorrect, the baud rate speed difference between the transmitting and receiving UARTs can only be roughly 10%. The most popular baud rates are 4800, 9600, and 115200 bits per second (bps). On the MS51FB9AE, UART0 and UART1 are available.
On the MS51FB9AE, UART0 and UART1 are full-duplex enhanced UARTs with automated address identification and framing fault detection. The registers that control these two UARTs are identified as two separate components. For UART activities, the MS51FB9AE features two pairs of RX and TX pins. Becase of it, the first step is to select the needed UART port for activities.
The I/O pins necessary for RX and TX communication must be set as input and output after selecting one UART (UART0 in this example). UART0's RX pin corresponds to the microcontroller's pin 3, which is Port 0.7. Port 0.7 must be configured as input because it is a serial port receive pin. Port 0.6, on the other hand, is a transmit or output pin on the microcontroller. Quasi bidirectional mode must be selected. These can be selected using the registers of PxM1 and PxM2. The I/O modes are defined by these two registers, where x is the port number. The SM0 and SM1 buttons select the UART operation modes (7th and 6th bits of the SCON register). Mode 0 is synchronous, whereas the other three are asynchronous. On the other hand, depending on the serial port mode, the Baud Rate generator and Frame bits alter. For the UART1, any mode can be used depending on the application's needs.
Applications:-
The A7672S features a variety of industrial standard interfaces with great expandability, including UART, USB, I2C, and GPIO, making it perfect for important IoT applications like:
Telematics
POS
Surveillance Devices
Industrial routers
Remote diagnostics