AC Board

Software interface description

This board mainly uses the internal resources of the Mega48 microcontroller, including USART, TIMER, and IO ports. The details are as follows:

1． USART: RXD, TXD, SEL-RT are communication ports, of which SEL-RT is the

communication enable port, and when the level is high, it transmits;

When the level is low, it is received. RXD and TXD are the receiving

and transmitting ports, respectively.

2． XTAL1 and XTAL2 are the input and output ports of the crystal oscillator.

3． SPI-MOSI, SPI-MISO, and SPI-SCK are the download control ports for ISPs.

4． CPU-Reset is the microcontroller reset level input port.

5． VREF-4.096 is the sampling reference input port

6． VAC-1U, VAC-1V, and VAC-1W are three-phase voltage sampling input ports.

7． The SPD is the lightning protection status signal input port.

8. ZA and ZB are in-place signal input ports.

Device description

According to the functions to be completed, the programmable device selected for this board is the single-chip microcomputer Mega48, and the code number in the board is D1. The main performance of the microcontroller includes:

1. High-performance, low-power 8-bit AVR® microprocessor

2. Advanced RISC structure

– 131 Instructions – Most instructions are executed for a single clock cycle

– 32 x 8 universal working registers

– Fully static operation

– Performance up to 20 MIPS at 20 MHz

– Hardware multiplier that only requires two clock cycles

3. Non-volatile programs and data memory

– 4K bytes of in-system programmable Flash erase life: 10,000 cycles
– Optional Boot code area with independent lock bits, enabling true simultaneous read and write operations programmed within the system through onchip Boot programs

– 256 bytes of EEPROM, erase and write life: 100,000 cycles

– 512 bytes of on-chip SRAM

– The lock bit can be programmed to encrypt the user's program

4. Peripheral features

– Two 8-bit timers/counters with independent prescaler and comparator functions

– A 16-bit timer/counter with prescaler, comparison and capture

– Real-time counter RTC with independent oscillator

– Six-channel PWM

– 8 x 10-bit ADCs (TQFP and MLF packages).

– 6 x 10-bit ADCs (PDIP package).

– Programmable serial USART interface

– SPI serial interface that can operate in master/ slave mode

– Byte-oriented two-wire serial interface

– Programmable watchdog timer with independent on-chip oscillator

– On-chip analog comparator

– Pin level changes can cause interrupts and wake up the MCU

5 .Operating Voltage:

– ATmega48V/88V/168V： 1.8 - 5.5V

– ATmega48/88/168： 2.7 - 5.5V

HOHUI Tech

AC voltage detection board

Basic principle:

Software interface description

Device description