BoSL Board v0.5

2023 September 28

The BoSL board rev 0.5.0 arrived and its time to test how it works. Lets jump into it!

Straight out of the packet:

• Plugging in a battery the idle current 840 µA.
• Touching a screw driver to the F1 TEST pad lights up the test LED.
• When the WDT_EN jumper is closed the current jumps up to ~10 mA. This seems appropriate, if it enables the voltage on VPP.

From now on WDT_EN will be closed

• Voltage is good on 3V3 and VBAT. Measured (3.370V and 3.941V respectively).
• The bootloader could be programmed using the normal process of Arduino as ISP. Specifically I used the [[1]] board library and selected the ATmega640 board. I then used BOD: 2.7V, bootloader: yes UART0, clock: external 8MHz, EEPROM: EEPROM retain, compiler LTO: LTO disabled, pinout: AVR pinout.
• Idle current now 18 mA.
• I then plugged in the board via USB and it was recognised as a serial port.
• Programs could be uploaded via USB now, the serial monitor analogue read, and the RX,TX, LED, and USB, LEDs work.

• I could get a response form the SIM7000 when I made the following changes to the BoSLpass script.
  • Replaced simCom soft serial object with Serial1
  • set PWRKEY 38, DTR 44, and defined SIM_BUF_EN 25
• Pulled SIM_BUF_EN HIGH to turn on the voltage level converter.

Firmware updates:

Now that we have the more pins it would we wise to wrap each call which writes to the serial of the SIM7000 to first check CTS and RTS and see that we can send.

Errors:

1. WDT_EN is not the correct name for the jumper as the WDT is disabled when closed. It should be not WDT_EN