Monarco-HAT-Hardware-Reference-Manual

Monarco HAT Hardware Reference Manual 20190728-1
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Real Time Clock (RTC) 4.6.
RTC chip type: MCP79410 with 32768 Hz crystal
Interface: I2C, address 0x6f (RTC/SRAM) + 0x57 (EEPROM)
Wiring: connected to Raspberry Pi I2C-1 and to MCU I2C
Battery type: CR1225 or CR1216
RS-485 Interface 4.7.
Transceiver chip type: SN65HVD75
Data rate: up to 20 Mbps (as per transceiver specification, limited by MCU USART)
ESD protection:
o Transceiver internal - IEC 61000-4-2 of up to ±12 kV, IEC 61000-4-4 of up to ±4 kV
o Additional - TVS Diode -7 V / +12 V around GND
Line load: 3/20 unit load (213 transceivers on line)
Line termination: on-board 120R termination resistor, software switchable
Wiring: Connected to MCU UART. Standard function is bidirectional forwarding to/from
Raspberry Pi UART with buffering and RS-485 Driver-Enable signal generation with proper
timing. Alternative functions can be implemented in MCU firmware.
1-Wire Interface 4.8.
Controller chip type: DS2482-100
Controller interface: I2C, address 0x18
Wiring: connected to Raspberry Pi I2C-1 and to MCU I2C
ESD protection: DS9503 chip
Note: 5 V output with software controlled power switch for network reset in case of stuck
Digital Inputs 4.9.
Optically isolated, common negative potential
Logic low voltage: -30 to 1.8 V
Logic high voltage: 3.5 to 30 V
Note: input low/high levels compatible with 5V CMOS logic
Input Resistance: 3 kOhm + typ. 1.5 V drop
Input current: typ. 7.5 mA at 24 V, 3.5 mA at 12 V, 1.2 mA at 5 V
Maximal input frequency: 500 kHz
Input propagation delay (typical / maximal): 70 ns / 100 ns
Dielectric strength: 300 V
Optocoupler type: TLP2161
Features:
a) Standard digital input, selectable input glitch filter (under development)
b) HW counter, 2 channels (DI1-DI2, DI3-DI4) with selectable function:
Pulse counter, optional direction signal
Quadrature encoder counter
Frequency / Period / Pulse length measurement (under development)
Note: counter on DI3-DI4 cannot be activated simultaneously with PWM2 on DO4.