# Peripherals



# Simplified Block Diagram

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<div drawio-diagram="1657"><img src="https://doc.redisage.com/uploads/images/drawio/2026-03/drawing-29-1772535754.png" alt=""/></div>

Optional elements are marked with the dashed lines.

# New Page



# New Page



# New Page



# RGB LED

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<div drawio-diagram="809"><img src="https://doc.redisage.com/uploads/images/drawio/2024-06/drawing-22-1718894620.png" alt=""/></div>

RGB LED is controlled by SIPO shift register 74HC595BQ.

- SHCP - shift register clock input
- STCP - storage register clock input
- DS - serial data input

# Switch

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<div drawio-diagram="806"><img src="https://doc.redisage.com/uploads/images/drawio/2024-06/drawing-22-1718894224.png" alt=""/></div>

The Open IoT Gateway P01 variant contains a tactile switch. The PCB has hardware pull-up designed into it so debouncing effect is eliminated.

<p class="callout warning">If the switch is soldered to the PCB, make sure there is also a resistor R52 located on the bottom layer of the board.</p>

# RS232 and RS485

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<div drawio-diagram="807"><img src="https://doc.redisage.com/uploads/images/drawio/2024-06/drawing-22-1718894516.png" alt=""/></div>

The gateway is equipped with 2 transceivers MAX481 that handle transmission in RS485 standard on each channel independently. Similar to RGB, each channel can be enabled by SIPO shift register 74HC595BQ.

To ensure transmission in RS232 standard there is also ST3232BTR IC which allows transmission on each channel independently.

<p class="callout info">It is possible to use only one pair of each interface at the same moment, because RS232 and RS485 use the same UART pins on the MCU.</p>

# Ethernet PHY

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<div drawio-diagram="810"><img src="https://doc.redisage.com/uploads/images/drawio/2024-06/drawing-22-1718894695.png" alt=""/></div>

The Ethernet interface is provided by the IP101G physical layer. There is also an external board with RJ45 socket which ensures wired connection to the network.

# MicroUSB

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<div drawio-diagram="811"><img src="https://doc.redisage.com/uploads/images/drawio/2024-06/drawing-22-1718894774.png" alt=""/></div>

MicroUSB ensures access straight to UART interface (UART0). The Open IoT Gateway does not have inbuild FTDI converter so an external USB to UART FTDI converter is needed to run a serial port monitor on a PC.

# I2C EEPROM

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<div drawio-diagram="812"><img src="https://doc.redisage.com/uploads/images/drawio/2024-06/drawing-22-1718895004.png" alt=""/></div>

# Antenna

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<div drawio-diagram="333"><img src="https://doc.redisage.com/uploads/images/drawio/2024-04/drawing-10-1712224333.png" alt=""/></div>

The Open IoT and IIoT Gateway P02 variant contains SMA connector for a 2.4G antenna.

# QSPI Flash

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<div drawio-diagram="814"><img src="https://doc.redisage.com/uploads/images/drawio/2024-06/drawing-22-1718895404.png" alt=""/></div>

# QSPI RAM

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<div drawio-diagram="1656"><img src="https://doc.redisage.com/uploads/images/drawio/2026-03/drawing-29-1772534963.png" alt=""/></div>

# Expander

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<div drawio-diagram="817"><img src="https://doc.redisage.com/uploads/images/drawio/2024-06/drawing-22-1718895879.png" alt=""/></div>

The female goldpin connector allows easy access to different signals. It might be useful during analysis of the board.

- GPI38 - general purpose input pin, connected directly to the MCU (might work only as an input pin)
- 3V3 - 3.3 V voltage
- I2C\_SCL and I2C\_SDA - main lines of the I2C interface
- GND - ground
- NC - not connected
- FGC - frame ground connection
- BUT\_EXT - switch test line ('1' is set by default)
- Q2 - Q2 pin of the shift register
- STCP - storage register clock input
- SHCP - shift register clock input
- Q7S - serial data output pin of shift register
- CHIP\_PU - chip power up signal ('1' - enables the chip)

# I2C Sensors

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<div drawio-diagram="813"><img src="https://doc.redisage.com/uploads/images/drawio/2024-06/drawing-22-1718895200.png" alt=""/></div>

- LSM6DS33 - 3D accelerometer and 3D gyroscope
- LIS3DH - 3-axis "nano" accelerometer
- HTS221 - capacitive digital sensor for relative humidity and temperature measurements
- SI7006-A20 / SI7020-A20 - humidity and temperature sensor
- Secure element