[Anxinke NB-IoT Development Board EC-01F-Kit] Part 1: Getting to know EC-01F-Kit

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[Anxinke NB-IoT Development Board EC-01F-Kit] Part 1: Getting to know EC-01F-Kit [Copy link]

1. First impression of the development board

Development board components: development board, antenna, mobile data card

2. Development board data learning

Main chip

The main chip is EC616S from Yixin Communication , which should be the company's second mass-produced NB-IOT chip. The following table shows the basic specifications of EC616 .

Chip model :EC616S

Frequency band :663MHz-2200MHz

Protocol version :3GPP R13/R14

Operating voltage :2.2V ~ 4.5V

Operating temperature :-40°C ~ +85°C

PSM power consumption : 0.8uA

IDLE power consumption (DRX 2.56s) : 0.11mA

Built-in PA output power :23dBm

CPU Core : Cortex-M3

Hardware peripherals :SPI×2, I2C×2, GPIO×16, UART×3, PWM×6, ADC×4, USIM×1

Package :QFN52 6mm*6mm*0.9mm

In addition, a piece of information directly related to the module evaluation is that by default , EC616S has the following usage definitions for its serial port 0 and serial port 1 :

• Serial port 0 is used as the log output port. The default log output baud rate is 3000000bps , i.e. 3Mbps .
• Serial port 1 is used as AT transceiver interface , and the default baud rate is 9600bps

Modules

The module model is EC-01F . The other two models are EC-01 and EC-01G . The parameters of these three modules are compared in the following table:

Below is the module schematic diagram from the module manual. On the right is the main chip EC616S and peripheral circuits, including the external clock crystal oscillator, RF filter circuit, etc.

Some notes on using the module:

• Recommended voltage: 3.3V-4.5V, peak current: 500mA or above
• It is recommended to use LDO power supply; if DC-DC is used, it is recommended to control the ripple within 50mV.
• It is recommended to reserve space for dynamic response capacitors in the DC-DC power supply circuit to optimize the output ripple when the load changes greatly.
• It is recommended to add ESD devices to the 3.3V-4.5V power interface.

Development board circuit

The development board includes the following circuits:

• 5V to 3.3V LDO
• Modules
• SMA antenna socket
• USIM card slot
• USB-UART Chip
• button
• led
• Connect the pin header

Note:

• In EC-01F-Kit V1.0, only one of the onboard Micro-USB port and TX1 or RX1 can be used for communication and programming. When the serial port chip exists, only the onboard Micro-USB port can be used for communication and programming. If you want to use the TX1 and RX1 pin headers for communication and programming, you need to remove the serial port chip. At this time, the Micro-USB port does not support communication and programming. In EC-01F-Kit V2.0, the Micro-USB port and TX1 and RX1 can be used for communication at the same time.
• By comparing Figure 9 in the development board document , it is confirmed that the chip version received is V1.0 . In addition, the development board schematic diagram in the document specification v2.0.1 should be the schematic diagram of the V2.0 version development board, not the schematic diagram of the V1.0 board. Please pay attention when using it.

3. AT communication problem solving process

After powering on the development board via USB, it was found that there was a problem with sending and receiving AT commands via USB ( USB - UART ) , specifically, there was no response after sending AT commands to the module.

I tried to update the module's firmware via USB and found that the firmware could be updated successfully.

After updating the firmware, I sent AT commands again, but there was still no response. I was a little panicked, wondering if I had encountered a bad board. I paused for a moment and looked through the previous evaluation reports. It seems that this is a common problem, and it seems that the problem points to the onboard CH340 USB -UART chip.

According to the inspiration, I took a USB to UART cable and used the pins TX1 and RX1 on the board to communicate directly. But it still didn't work. I used an oscilloscope to measure the waveform. The signal waveform sent to the module was incorrect. The low level was too high and could not be pulled to the ground at all. The onboard USB-UART chip and the external cable both used TX1 and RX1 . There was a conflict between the two parts, resulting in incorrect signals.

After thinking about it, I finally made up my mind to remove the CH340 . I did it right away. I found a soldering iron that I hadn't used for a long time and quickly removed the chip. I used the USB to UART cable again to send AT commands. After trying a few commands, I suddenly received data sent back by the module. After that, the AT command worked every time.

Jacktang

For communication issues, please refer to the review by netizen kit7828

Is it

https://bbs.eeworld.com.cn/thread-1189540-1-1.html

oxygen_sh

Because the development board I got is version V1.0, when connecting to other MCUs through the extended PIN TX1/RX1, you need to remove CH340. Later, I carefully read the information of the development board and found that it is actually written in the document. Thanks @Jacktang for the reminder!