Reverse Engineering ROCKTECH ISG-502

Description

The Board has the printed text: RPI_300_EXT_V1_0. The Housing has the Model ISG-502 printed on a label.

The Case has following connectors:
• 9-24 V DC
• LED PWR
• LED STATUS
• IO0, IO1, IO2, IO3, GND
• B0, A0 - RPI UART
• GND,
• B2/RX1, A2/TX1 - RS232 CH432 UART0
• B1/RX0, A1/TX0 - RS485 CH432 UART1

It has true RS232 and RS485 interfaces on green 3,5mm Phoenix(?) connectors. Inside is also a Realtimeclock (Epson RX8010) with backup battery. The 9-24V DCDC converter seems to to be to weak for 5V 4A to RPi4.

Help wanted: If you are able to work with the CH432 UART or RTC: Please let me know, so that all readers get this information!

Details

Let me know if this document contains something, what not should be public!

If you have such a board and have details about RTC, serial, DCDC, please let me know!

If you are able to use serial or RTC from software, pleas let me know it!

The main components are:

U7 + U9: SP3483, SO08, 3.3V Low Power Slew Rate Limited Half-Duplex RS-485 Transceiver
Q2: SOT23 702: 2N7002, N-Channes Mosfet
Y1 22.1184 MHz Quarz
U3: WCH CH432T SSOP20 SPI dual UART
U8 Sipex SP2323EE True RS232 Transceiver
U4 Epson RTC R8010, I2C und 2x IRQ
Q1 NPN Transistor 1AM = MMBT3904L
U2 1117 3,3Volt Low Dropout Voltage Regulator
SS34 40V 3A Shottky Diode
U1 AHHCY6 DCDC regulator
U12 TXS0102DCUR FE NZ dual Level shifter
Diode CG_ TVS Diode 28V
BAT54C SOT23 Marking TL3
ESD Diode Marking AC: PESD5V0L1BA, Low capacitance bidirectional ESD protection diode SOD323

The known Pins are: