AVR Project PCB

This is a PCB for prototyping with an ATmega*8 microcontroller. Eg. build a stable prototype of an AVR project, that have been created on a bread board or Arduino before.

Features

AVR ATmega 8 / 48 / 88 / 168 / 328.
Project area for analog and digital circuits.
Standard 6 pin AVR programming connector.
Area for connectors with up to 30 pins total.
6 power MOSFET's including current limiting resistor.
Two supply voltages, VCC (+5V) and VBATT (any 'reasonable' voltage).
5V voltage regulator.
Configurable connector for serial converter (eg. USB or Bluetooth).

Components

Name	Value	Description
C2	100nF	Blocking capacitor for AVR.
C3	100nF	AREF capacitor.
C6	>= 10uF	VCC capacitor.
C7	100nF	VCC capacitor.
C8	>= 10uF	VBAT capacitor (add only when VBAT is needed).
C9	100nF	VBAT capacitor (add only when VBAT is needed).
P3	2x3pin	Programming connector.
R1	10k	Pull-up resistor for reset.
SW1	6*6mm	Reset button.
U1	ATmega*8	Microcontroller.
Optional Crystal
X1	18.432MHz	or your preferred frequency.
C4, C5	22pF	Capacitors for the crystal.
AVCC Filter (Jumper J1 needs to become opened)
L1	???	Filtering inductor.
C1	100nF	Blocking capacitor.
Varia
Q1-6	IRL3705 / IRF4905	Power transistors/MOSFET's.
U2	7805 (LM1117 or similar regulator)	+5V voltage regulator (don't forget to add C8 & C9).
	small power connector	1=GND, 2=V+. KF2510 (also to be used for connector area on the top).
	large power connector	1=GND, 2=V+. VH 3.96mm (when there is more equipment using Vbat, the small connector should be used to distribute power to it).

Solder Jumpers

Name	Signal	Description
J1	AVCC	Disconnects VCC from AVCC to add appropriate induction L1. Also add C1 = 100nF
J2	VX2	Connects VCC or VBAT to the VX2 line on the project area.
J3	VX3	Connects VCC or VBAT to the VX3 line on the project area.
J4	PB6	Connects PB6 (crystal) to the AVR lines on the project area.
J5	PB7	Connects PB7 (crystal) to the AVR lines on the project area.
J6	PC6	Connects /RESET to the AVR lines on the project area.
J7	J7V	Connects VCC or VBAT to J7V of J9, J11, J13.
J8	J8V	Connects VCC or VBAT to J8V of J10, J12, J14.
J9	Q1S	Connects GND or J7V to the source of Q1.
J10	Q2S	Connects GND or J8V to the source of Q2.
J11	Q3S	Connects GND or J7V to the source of Q3.
J12	Q4S	Connects GND or J8V to the source of Q4.
J13	Q5S	Connects GND or J7V to the source of Q5.
J14	Q6S	Connects GND or J8V to the source of Q6.
J15	VX1	Connects VBAT to the VX1 line on the project area.
J16	AREF	Connects AREF to the AVR lines on the project area.

Transistors/MOSFET's and PWM

The gate pins of Q1 to Q6 are wired to corresponding G1 to G6 on the top of the board, where they are nearby the column of the AVR's PWM output:
- G1 -> PD6 - OC0A (AIN0)
- G2 -> PD5 - OC0B (T1)
- G3 -> PB1 - OC1A
- G4 -> PB2 - OC1B (/SS)
- G5 -> PB3 - OC2A (MOSI), (one pin to the left)
- G6 -> PD3 - OC2B (INT1)
When using N-type FET (IRL3705) at position Q1, Q3 and Q5, the source pin may connected to GND by setting Jumper J9, J11 and J13 to GND correspondingly.
If more N-type FET are needed, place them at postition Q2, Q4 and Q6. The source pin may become GND by setting J10, J12 and J14 to GND correspondingly.
For P-type FET (IRF4905) on position Q1, Q3 and Q5, the Jumper J7 selects VCC or VBAT to be connected to the source pin via corresponding Jumper J9, J11 and J13 set to VJ7.
Similar when using P-type FET on position Q2, Q4 and Q6: Jumper J8 selects the voltage (VCC or VBAT) to be connected to the source pin with corresponding Jumper J10, J12 and J14 set to VJ8.
When in drain path of Q1 to Q6 a (power)resistor is needed, it can be placed at postition QxD to Ox correspondingly. The output leads to O1 - O6 on the upper, left corner near the connector area.

HBUS, Signal distribution at Connector Area

The HBUS can be used to horizontally distribute signals nearby the connector area. All "1" are connected to each other, all "2" and so on. 5 times up to 6 signals may be distributed.

Serial I/O Option

Add serial to usb board (also bluetooth or similar possible) to SER-USB in appropriate socket and connect via separate row of pins to VCC, PD1(AVR-TXD), PD0(AVR-RXD) and GND.
Attention: Connect RXD of USB-SER to AVR-TXD and vice versa!

Ridiculous Pin Naming

If you are using that monstrosity called Arduino the following table might come in handy for translating those ridiculous pin names. Please also make sure you use Arduino compatible resistors, LEDs, etc.

DIL Pin	AVR Port	Functions	Arduino
2	PD0	RXD	digital pin 0
3	PD1	TXD	digital pin 1
4	PD2	INT0	digital pin 2
5	PD3	OC2B, INT1	digital pin 3
6	PD4	XCK, T0	digital pin 4
11	PD5	OC0B, T1	digital pin 5
12	PD6	OC0A, AIN0	digital pin 6
13	PD7	AIN1	digital pin 7
14	PB0	CLKO, ICP1	digital pin 8
15	PB1	OC1A	digital pin 9
16	PB2	SS, OC1B	digital pin 10
17	PB3	MOSI, OC2A	digital pin 11
18	PB4	MISO	digital pin 12
19	PB5	SCK	digital pin 13
23	PC0	ADC0	analog input 0
24	PC1	ADC1	analog input 1
25	PC2	ADC2	analog input 2
26	PC3	ADC3	analog input 3
27	PC4	ADC4, SDA	analog input 4
28	PC5	ADC5, SCL	analog input 5