1. The document shows a circuit diagram for a microcontroller board using an ATmega128 microcontroller. 2. Key components include the microcontroller U3, voltage regulators VR1 and U1, oscillators Y1 and X1, and various input/output ports and connections. 3. The circuit provides power regulation and input/output interfaces to connect sensors, displays, and other peripherals to the microcontroller.

1. 1 2 3 4 5 6
+5V
VR1 +5V
10k H1
CONTRAST 1 2
PA0 PA1
H7 PA2 3 4 PA3
+V 1 2 GND R1 PA4 5 6 PA5
3 4 10k U1 7 8
PG4 RS VO PA6 PA7
A PD7 EN 5 6 RW RST 20 44 PA7 9 10 A
+5V
RESET (AD7)PA7
D1 7 8 D0 45 PA6
3
4
C1 22pF (AD6)PA6
D3 9 10 D2 SW1 23 XTAL2 (AD5)PA5 46 PA5 PA0-PA7
PG1 D5 11 12 D4 PG0 RESET 47 PA4
Y1 (AD4)PA4 H2
C2 22pF
1
2
PG3 D7 13 14 D6 PG2 24 XTAL1 (AD3)PA3 48 PA3
16MHz (AD2)PA2 49 PA2 PB0 1 2 PB1
ET-CLCD L1 R2 0R 62 50 PA1 PB2 3 4 PB3
AREF (AD1)PA1
64 51 PA0 PB4 5 6 PB5
+5V
+5V AVCC (AD0)PA0
bead 63 PB6 7 8 PB7
+
+5V GND
H8 C3 C4 17 PB7 9 10
+5V
H9 (OC2/OC1C)PB7
PE0 1 2 10uF 100n 52 16 PB6
+5V
VCC (OC1B)PB6
3 4 PE1 1 2 21 VCC (OC1A)PB5 15 PB5 PB0-PB7
RST 5 6 PB1 3 4 PE0 C6 C7 22 14 PB4
C5 100n 100n GND (OC0)PB4 H3
PB1 7 8 RST 5 6 100n 53 GND (MISO)PB3 13 PB3
PE1 9 10 (MOSI)PB2 12 PB2 PC0 1 2 PC1
AVR ISP PG3 18 PG3(TOSC2) (SCK)PB1 11 PB1 PC2 3 4 PC3
AVR ISP +5V 10 PB0 PC4 5 6 PC5
(SS)PB0
B PG4 19 PG4(TOSC1) PC6 7 8 PC7 B
U2 42 PC7 9 10
+5V
C8 (A15)PC7
16
1 C1+ C10 PG2 43 PG2(ALE) (A14)PC6 41 PC6
VCC
V+ 2 100n PG1 34 PG1(RD) (A13)PC5 40 PC5 PC0-PC7
100n 3 C12 PG0 33 39 PC4
C1- U2P 100n PG0(WR) (A12)PC4 H4
6 1 38 PC3
+5V
C9 V- 100n PEN (A11)PC3
GND
4 C2+ R3 (A10)PC2 37 PC2 PD0 1 2 PD1
15
C11 10k 36 PC1 PD2-H4 3 4 PD3-H4
100n (A9)PC1
5 C2- (A8)PC0 35 PC0 PD4 5 6 PD5
PD6 7 8 PD7
11 14 32 PD7 9 10
+5V
T1IN T1OUT (T2)PD7
10 T2IN T2OUT 7 (T1)PD6 31 PD6
12 13 +5V 30 PD5 PD0-PD7
R1OUT R1IN J1 (XCK1)PD5
9 R2OUT R2IN 8 (ICP1)PD4 29 PD4
1 28 PD3 H5
(TXD1/INT3)PD3
ICL3232 RXD0 2 (RXD1/INT2)PD2 27 PD2 PE0-H5 1 2 PE1-H5
R8 R5 R7 R4 TXD0 3 26 PD1 PE2 3 4 PE3
C 0R 330R 0R 330R 4
(SDA/INT1)PD1
(SCL/INT0)PD0 25 PD0 PE4 5 6 PE5 C
PE6 7 8 PE7
1 1 1 1 RS232-CH0 PF7 54 9 PE7 9 10
+5V
RS232 PF7(ADC7/TDI) (ICP3/INT7)PE7
2 2 2 2 +5V PF6 55 8 PE6
J2 PF6(ADC6/TDO) (T3/INT6)PE6
3 3 3 3 PF5 56 PF5(ADC5/TMS) (OC3C/INT5)PE5 7 PE5 PE0-PE7
JP2 JP3 JP4 PORT 1 PF4 57 6 PE4
JP1 PF4(ADC4/TCK) (OC3B/INT4)PE4
RXD1 2 PF3 58 5 PE3 H6
PD3-H4
PD2-H4
PE1-H5
PE0-H5
PF3(ADC3) (OC3A/AIN1)PE3
TXD1 3 PF2 59 PF2(ADC2) (XCK0/AIN0)PE2 4 PE2 PF0 1 2 PF1
PD3
PD2
PE1
PE0
4 PF1 60 PF1(ADC1) (TXD0/PDO)PE1 3 PE1 PF2 3 4 PF3
PF0 61 PF0(ADC0) (RXD0/PDI)PE0 2 PE0 PF4 5 6 PF5
H10 H11 RS232-CH1 PF6 7 8 PF7
+5V 1 +5V 1 9 10
+5V
ATMEGA128
2 2
3 3 PF0-PF7
4 4 LOGO ETT
J3
6-12VDC
D 3 U3 +5V D
C13 C15
2 D1
100uF/25V
KIA278R05
470uF/16V
R6
560R
Sheet Title:
1 1 VIN VO 2
Project Title: ET-BASE AVR MEGA128 Size: A4
+
+
S1G C14 C16 LED1
100n 4 CONT GND 3 100n PWR
Drawn By: ETT CO., LTD. REV: 3
Date: 23/9/2553 15:25:44 Sheet: 1/1
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