OpenM128

OpenM128 Standard AVR Development Board AVR development board designed for ATMEL mega AVR, features the ATmega128 MCU, and integrates various standard interfaces, pretty easy for peripheral expansions.

OpenM128 Package A AVR Development Board

OpenM128 Package B AVR Development Board

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Primary Attribute Category: MCU Tools, AVR, AVR Development Boards {{{userDefinedInfo}}}: {{{userdefinedvalue}}} Brand: Waveshare

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Onboard Interfaces

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Introduction

AVR development board designed for ATMEL mega AVR, features the ATmega128 MCU, and integrates various standard interfaces, pretty easy for peripheral expansions.

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Overview

This user manual contains schematic and demo of Waveshare OpenM128 development board. It helps you to quick start your AVR development.

Hardware design

This chapter mainly about a basic idea of the hardware design of OpenM128. Go with you to witness how a ATmega128A-AU chip becomes OpenM128 board.

First of all, we start from the common LED demo. This demo is an example of flashing alternately LED, controlled by the MCU. How do the MCU finish such a common demo? And what circuit work together?

For the MCU system, actually its program controls the I/O pins to output high or low to turn on or turn off the LEDs. And the time span of the high or low output controls the time span of light up. Surely, the chip needs power supply to work; it needs clock circuit to control LED blink time; it needs Download/Configure circuits to program the compiled project; it needs reset circuits to reset and begin again. The pins of chip can be divided into I/O, SPI, I2C, USART interfaces and so on according to the features.

Power supply circuit, a clock circuit, reset circuit and configuration circuit in above-mentioned are the necessary circuits of MCU development. So, many minimum system board just have these circuits and won't extend other feature interfaces. However, OpenM128 extends all chip interfaces of different kinds and gives you supporting function modules and drivers. Helps you to quick start all feature interfaces learning and to develop similar extends. A variety of circuits will be introduced in the following chapter.

Power Supply Circuit

Power supply circuit is the basic circuit to drive OpenM128 development board. We can find that ATmega128A-AU works on 2.7V~5.5V in the datasheet. And the board is designed for both 5V and 3.3V. The AMS1117-3.3 onboard is used for converting 5V to 3.3V, you can set the jumper to convert the MCU input voltage between 3.3V and 5V. In addition, the power supply circuit contains control switch, power LED, 3.3V/5V/GND pin out, that make control and inspection of power supply circuit more easily.

Pin Name	Description
5V	5V supply input, it can be used as MCU or other peripherals VCC power supply.
3.3V	3.3V supply from AMS1117-3.3, it can be used as MCU or other peripherals VCC power supply.
GND	Ground
VCC	It is a pin corresponding to MCU VCC, you can set the jumper to convert the MCU input voltage between 3.3V and 5V.
PWR_5V	5V input from a power supply.

Clock Circuit

There is a calibrated RC oscillator in the AVR MCU. So usually, extended clock circuit can be removed under less demanding circumstances on clock accuracy. For higher clock accuracy demand, OpenM128 is designed relative flexibly, it supplies optional oscillator crystal ports besides of onboard 7.3728M and 32.768K crystal. If the MCU RC oscillator is not suit your requirement, you can connect a right crystal and set the XTALn jumper to switch between XTAL1 and XTAL2.(Note: the corresponding fuse bit should be set by the program.)

Pin Name	Description
XTAL1	Inverting oscillator amplifier and on-chip clock operating circuit input
XTAL2	Inverting oscillator amplifier output
PG3	I/O pin, it can also be used as 32kHz crystal input
PG4	I/O pin, it can also be used as 32kHz crystal input

Reset Circuit

Reset of AVR chip is low active, mean while that a 50 ns low signal input to reset pin will cause the chip reset. When you press the reset button, reset pin connects to negative power supply, and then, when you release the button, although the reset pin convert to high, actually the pressing time is more than 100 ms usually, it was enough for chip reset pulse transmission.

Pin Name	Description
nRST	Chip reset, low active

Download/configure circuit

Download, also known as programming, is a chip programming and configuration process. AVR MCUs support ISP, JTAG, PDI download and so on. The first two are more commonly used. OpenM128 extends 2 kinds of download interface, they are a 10-pin-ISP, a 6-pin-ISP and a 10-pin-JTAG. You can connect standard AVR programmer or debugger on it directly. You can download by JTAG or ISP, but only the JTAG interface supports both download and on-chip debug.

Pin Name	Description
MISO	ISP, master in slave out (serial peripheral interface)
MOSI	ISP, master out slave in (serial peripheral interface)
SCK	ISP, Serial Clock，ISP operation is synchronous to SCK.
TDI	JTAG, JTAG Test Data In: Serial input data to be shifted in to the Instruction Register or Data Register(scan chains).
TDO	JTAG, JTAG Test Data Out: Serial output data from Instruction Register or Data Register.
TMS	JTAG, JTAG Test Mode Select: This pin is used for navigating through the TAP-controller state machine.
TCK	JTAG, JTAG Test Clock: JTAG operation is synchronous to TCK.

Extension Circuit

OpenM128 has various expansion circuit and the onboard LED, button ... make I/O operation easily; Some extensions, such as LCD, 16I/O, USART, PWM, I2C, SPI and so on, are not only the literal meaning for beginners. If you master these function interfaces, you will realize infinite charm from SCM. Many available powerful peripheral modules, GPS, WIFI, Graphic, Vedio, Intelligent recognition, can be interfaced to a variety of MCU. If all these modules were integrated into your development board, what surprising thing will you make!

Basic Operation

Power Up and Download

Connect the programmer to your OpenM128 as shown in the following figure.

Quick Start Demo

To use the following quick start demo, You should power up and download corresponding program to your board.

2.2inch LCD_Display

Demo Description

• 2.2inch Display Demo

Operation

Steps

1. Take away the jumper 12864 JMP
2. Connect 2.2inch 320x240 Touch LCD (A) to LCD interface.
3. Power up and download the program.

Phenomenon

• 2.2inch LCD will show different colored block.

Photos

2.2inch LCD_Touch

Demo Description

• 2.2inch Touch Demo

Operation

Steps

1. Take away the jumper 12864 JMP
2. Connect 2.2inch 320x240 Touch LCD (A) to LCD interface.
3. Power up and download the program.

Phenomenon

• You will paint on the screen by touching and moving.

Photos

8 Push Buttons

Demo Description

• Press 8 Push Buttons to turn on or turn off the corresponding LEDs.

Operation

Steps

1. Check the LED jumper position on the board, jumpers LED JMP on.
2. Connect 8 Push Buttons module to the GPIO interface.
3. Power up and download the program.

Phenomenon

• Press key K0~K7, The corresponding LED will light up.

Photos

8 SEG LED Board

Demo Description

• Control 8 SEG LED Board via I/O port.

Operation

Steps

1. Connect 8 SEG LED Board to 16 I/Os port.
2. Power up and download the program.

Phenomenon

• You will see four of the onBoard 8-SEG-LED will show numbers or English letters regularly.

Photos

AD Keypad

Demo Description

• Print A/D key value from the UART port. AD Keypad module has 16 keys but occupies only one AD I/O, helps you to save limited I/O resources.

Operation

Steps

1. Connect AD Keypad to ADC interface.
2. Connect PL2303 USB UART Board (mini) to USART0.
3. Power up and download the program.
4. Check your COM port and set baud rate to 9600.

Phenomenon

• COM port will receive A/D Key value.

Photos

I2C_AT24CXX

Demo Description

• Read and write AT24CXX EEPROM via I2C interface.

Operation

Steps

1. Connect AT24CXX EEPROM Board to I2C interface.
2. Connect PL2303 USB UART Board (mini)
3. Power up and download the program.
4. Check your COM port and set baud rate to 9600.

Phenomenon

• COM port will receive the data read from and written to EEPROM.

Photos

I2C_PCF8563

Demo Description

• Read and write the clock of PCF8563 RTC Board via I2C interface.

Operation

Steps

1. Connect PCF8563 RTC Board to I2C interface
2. Connect PL2303 USB UART Board (mini)
3. Power up and download the program.
4. Check your COM port and set baud rate to 9600.

Phenomenon

• COM port will receive the data from RTC Board.

Photos

IO_FT245

Demo Description

• Read and write FT245 FIFO data via I/Os.

Operation

Steps

1. Take away the output-power-supply jumper from FT245 USB FIFO Board .
2. Connect PC0~PC7 to LED0~LED7 with jumper wire.
3. Connect the pin side of FT245 USB FIFO Board to 16 I/Os interface and the USB side to PC.
4. Power up and download the program.
5. Check your COM port and set baud rate to 19200.

Phenomenon

• COM port will receive ordered string 1~9. Some LED will be turned on corresponding to the COM port sending, For instance, if you send 0xCC, the LED will light up as binary "11001100".

Photos

Interupt_KEY4

Demo Description

• Use chip external interrupt, triggered from KEY4, to control the LED.

Operation

Steps

1. Jumper LED_JMP ON.
2. Power up and download the program.

Phenomenon

• Press KEY4, LEDs will light up increased, according to how many times the key pressed.

JOYSTICK

Demo Description

• LEDs' on or off will be switched according to JOYSTICK status.

Operation

Steps

1. Set jumper LED JMP and JOYSTICK JMP ON.
2. Power up and download the program.

Phenomenon

• Pull the Joystick to different position, the LEDs will be changed accordingly.

Photos

KEY

Demo Description

• LEDs' on or off will be switched according to the Key pressed.

Operation

Steps

1. Jumper LED JMP and KEY JMP ON
2. Power up and download the program.

Phenomenon

• Press KEY1~KEY4 separately, LEDs will be changed accordingly.

Photos

LCD12864

Demo Description

• Control screen LCD12864 by SPI and I/O interface.

Operation

Steps

1. Jumper 12864 JMP ON. Warning: jumper VCC should be set to 3.3V, or too large voltage will cause LCD too bright and burned.
2. Connect LCD12864 to LCD interface.
3. Power up and download the program.

Phenomenon

• LCD12864 will show "waveshare".

Photos

LED

Demo Description

• Control LCDs by chip's I/O port.

Operation

Steps

1. Jumper LED JMP ON.
2. Power up and download the program.

Phenomenon

• 8 LEDs status will be toggled.

Photos

ONE WIRE_DS18B20

Demo Description

• Measure the temperature of DS18B20+ by One Wire port.

Operation

Steps

1. Connect DS18B20+ to ONE WIRE port. Warning: Please make sure DS18B20+ is connected correctly to the ONE WIRE port, Arc side of DS18B20+ must match the sign of ONE WIRE port. Do NOT connect it reversely, or it may be burned.

1. Connect PL2303 USB UART Board (mini).
2. Power up and download the program.
3. Check your COM port and set baud rate to 9600.

Phenomenon

• COM port will receive corresponding temperature.

Photos

PS2

Demo Description

• Use PS/2 keyboard via PS/2 interface.

Operation

Steps

1. Jumper PS/2 JMP ON.
2. Connect PS/2 keyboard to PS/2 interface.
3. Connect PL2303 USB UART Board (mini).
4. Power up and download the program.
5. Check your COM port and set baud rate to 9600.

Phenomenon

• COM port will receive corresponding information input from the keyboard.

Photos

SPI_AT45DBXX

Demo Description

• Read and write AT45DBXX DataFlash Board, an external expansion memory module board, via SPI interface.

Operation

Steps

1. Connect AT45DBXX DataFlash Board to SPI interface
2. Connect PL2303 USB UART Board (mini).
3. Power up and download the program.
4. Check your COM port and set baud rate to 9600.

Phenomenon

• COM port will receive the data read from and written to DataFlash.

Photos

SPI_NRF24L01

Demo Description

• This is a demo of NRF24L01 wireless communication.

Operation

Steps

1. Prepare two OpenM128 and two NRF24L01 boards, for sending, TX, and receiving, RX, data. The following is an example of 2 OpenM128 boards.
2. Connect two NRF24L01 RF Boards to the SPI interface of OpenM128 boards separately.
3. Connect the RX board to a PC via PL2303 USB UART Board.
4. Power up and download the program.
5. Check your COM port and set baud rate to 9600.

Phenomenon

• COM port will receive the data from TX board to RX board.

Photos

T_C0_LED

Demo Description

• Control LEDs' status by I/Os and Timer 0(T/C0).

Operation

Steps

1. Jumper LED_JMP ON.
2. Power up and download the program.

Phenomenon

• 8 LEDs status will be toggled.

Photos

USART

Demo Description

• USART0：USART0 self-send-self-receive test.
• USART1：USART1 to send 'U' automatically.

Operation

Steps

1. Connect PL2303 USB UART Board (mini) to UART0 (or UART1)
2. Power up and download the program.
3. Check your COM port and set baud rate to 9600.

Phenomenon

• USART0：The information sent by PC's COM port will be received from the same port.
• USART1：USART1 will send 'U' automatically.

Photos

USART_Printf

Demo Description

• COM port will receive the data from USART0 interface.

Operation

Steps

1. Connect PL2303 USB UART Board (mini) to UART0.
2. Power up and download the program.
3. Check your COM port and set baud rate to 9600.

Phenomenon

• The program will send data via USART0 automatically, and then, COM port will receive the data from USART0 interface.

Photos

Resources

• Schematic
• Demo
• Datasheets
• Software
• Application Notes

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