Functional Description

Overview

As going by the word “mono” & “Zero”, monoZero represents monoZ's first thing in IoT space. monoZero is a compact and powerful cellular connectivity enabled development kit loaded with several peripherals allowing users to easily connect and control their sensors or other devices. This board is stackable with other add-on boards of the monoZero ecosystem and can be configured with monoZ: SDK libraries to reduce go to market time.

Features

• SIM7080G modem
  • Global connectivity supporting
    • CAT-M: B1/B2/B3/B4/B5/B8/B12/B13/B14/B18/B19/B20/B25/B26 /B27/B28/B66/B85
    • CAT-NB: B1/B2/B3/B4/B5/B8/B12/B13/B18/B19/B20/B25/B26/B28 /B66/B71/B85
  • Supports PSM and eDRX modes to extend battery life
  • LTE RF Power Class: 5 (Typ. 21dbm)
• STM32L4 MCU
  • ARM Cortex M4 32-bit processor @ 80MHz
  • 1MB flash, 320KB RAM
  • Ultra-low-power with FlexPowerControl
  • RTC with HW calendar, alarms and calibration
• Mixed signal GPIOs, UART, I2C, SPI, CAN
• SWD Connector
• RGB status LED
• Reset buttons
• Nano SIM
• SMA connector for external antenna

Board layout

• Micro USB port-1 - USB 2.0 Micro B port for power and debug input
• Power selector - Toggle the power input between USB and V_EXT input pin
• LED1 - GPIO LED
• LED2 - Power LED
• Connector-J4 - 40 pin connector
• Connector-J3 - 40 pin connector
• LTE-M / NB-IoT modem - SIM7080G modem
• STM32 MCU - STMicroelectronics 32 bit processor based on the Arm® Cortex®-M4
• Powerkey Button – Powerkey button to enable the power for the modem
• LED3 - Modem LED
• Micro USB Port -2 - USB 2.0 Micro B port for modem firmware update
• Antenna port - Female connector for RP SMA Male type antennas that can be used for high frequency from 2.4GHz - 2.6GHz
• SWD - Serial Wire Debug is used for binary flashing
• Input selector switch - Switch to toggle the modem input between STM32 and External

• SD card slot - External SD card slot
• Nano SIM slot - Slot for Nano SIM cards coming in at 8.8 x 12.3mm

Interfaces

Block diagram

SWD

monoZero has a dedicated 3-pin (SWDIO/SWCLK/GND) debug connector that exposes the SWD interface of the MCU. SWD uses an ARM CPU standard bi-directional wire protocol, defined in the ARM Debug Interface v5. This enables the debugger to become another AMBA bus master for access to system memory and peripheral or debug registers. This interface can be used to access MCU to program your monoZero to perform required function using standard SWD tool.

Antenna

Provision for Cellular antenna has been provided through an SMA female connector. Any corresponding Antenna (RP SMA Male) adhering to the following specification can be used to enable cellular connectivity.

• Impedance 50 ohm
• Input power > 23dBm Average power
• VSWR absolute max ≤ 10:1 (limit to avoid permanent damage)
• VSWR recommended ≤ 2:1 (limit to fulfill all regulatory requirements)

Power input

Standard 5V input voltage is to be supplied via micro-USB port or via external voltage input in connector J3 or J4. The power selector toggle switch is used to toggle between micro-USB port or external voltage input.

Peripherals and GPIO

Type	Qty	Input(I)/Output(O)
GPIOs	30	I/O
USB	2	I/O
LPUART	1	I/O
USART	1	I/O
I2C	2	I/O
SPI	3	I/O

Pinout and Description

• Connector J3

Pins	Pin No.	Description
VIN	p1	Input voltage supply
5V	p2,p7,p9	5V Output supply
3V3	p4,p6,p11	3.3V output supply
1V8	p8	1.8V output supply
GPIOs	p13,p14,p15,p16, p18,p20,p22,p23, p25,p27,p29,p31, p32,p34,p36,p38, p40	I/O pins
LPUART1	p24,p26,p28,p30	Provides UART communication upto 220KHz
SPI2	p33,p35,p37,p39	Synchronous communication upto 40MHz
I2C4	p17,p19,p21	Supports 100KHz-400KHz communication speed
GND	p3,p5,p10,p12	Ground connection for circuit

• Connector J4

Pins	Pin No.	Description
VIN	p1	Input voltage supply
5V	p2, p7, p12	5V Output supply
3V3	p4,p6	3.3V output supply
1V8	p8,p16	1.8V output supply
GPIO	p15,p17,p19,p21, p23,p25,p27,p29, p31,p33,p35,p37, p39	I/O pins
I2C2	p9,p11,p13	Supports 100KHz-400KHz communication speed
USART3	p26,p28,p30,p32	Bidirectional communication with high speed upto 204KHz
SPI1	p18,p20,p22,p24	synchronous communication upto 40MHz
SPI3	p34,p36,p38,p40	synchronous communication upto 40MHz
GND	p3,p5,p10,p14	Ground connection for circuit

Mechanical specifications

• Operating Temperature: -10 °C to 40 °C
  
• Dimensions : 90 mm x 65 mm
  
• Weight : *45 grams
  

Schematic

MCU

Modem

Power supply