A

B

C

D

E

fb_inj1

4

4

fb_inj2

3

JS6 Jmp

1

JS7 Jmp

1

Vsyn

JS8 Jmp

1

CGMXFC-1 OSC2-1 OSC1-1

JS9 Jmp

1

JS0 Jmp

1

JS1 Jmp

1

JS2 Jmp

1

JS3 Jmp

U1

JS10 Jmp

1

JS11 Jmp

1

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

Squirt-1 Accel-1 Warmup-1 TXD-1 RXD-1 IRQ-1

2

R1 10K

1

1

C1 VCC

0.1

VDDA VSSA CGMXFC OSC2 OSC1 RST PTC0 PTC1 PTC2 PTC3 PTC4 PTE0/TxD PTE1/RxD IRQ1 PTD0/SS PTD1/MISO PTD2/MOSI PTD3/SPSCK VSS VDD

PTA7/KBD7 PTA6/KBD6 PTA5/KBD5 PTA4/KBD4 PTA3/KBD3 PTA2/KBD2 PTA1/KBD1 PTA0/KBD0 VSSAD VDDAD PTB7/AD7 PTB6/AD6 PTB5/AD5 PTB4/AD4 PTB3/AD3 PTB2/AD2 PTB1/AD1 PTB0/AD0 PTD5/T1CH1 PTD4/T1CH0

3

FP-1

Idle-1

Vref AD5-1

AD4-1

1

JS4 Jmp

1

JS5 Jmp

AD3-1

AD2-1

AD1-1

AD0-1 PWM0-1

PWM1-1 2

68HC908GP32 CPU (or MS-II Daughtercard)

Note 1: For MS-II daughtercard implementation, the following signals apply to DIP-40 socket: 6 - CANHout 11 - CANLout 16 - V12 for IAC stepper 17 - IGN 18 - Knk Window 35 - IAC2B 36 - IAC2A 37 - IAC1B 38 - IAC1A Note 2: Jumper location JS9 (pin 16) tied to +12V for MS-II CPU board implementation for enabling IAC stepper driver. A

40 39 38 37 36 35 34 33 32 31 30 29 28 27 26 25 24 23 22 21

B

C

1

Title Size A Date:

Megasquirt - CPU - B. A. Bowling Document Number Rev 3.00 _ Mod Nov 2004 Sunday, April 17, 2005 D

Rev 2.991 Sheet

1

of E

8

A

B

C

D

E

R2

Vref

4

NC 2

5

Agnd NC

3

C3 U2 0.1 4 NC

C2 0.22

Out

AD0-1

V12

Manifold Absolute Pressure

Apwr

6

1K-1/4W

4

1

Vref

MPX4250AP

R3 50K

R4 R5

MAT

2.2K-1/4W C4 0.001

AD4-1

2.49K-1/4W

AD1-1

C5 1.0

R6 10K

Manifold Air Temp

Bootloader Entry H1

R7 3

1 2

R8

CLT

AD2-1 C6 2.2K-1/4W 0.001

Header

2.49K-1/4W

C7 1.0

3

Battery Voltage Coolant Temp

R9

TPS

AD3-1 C8 1K-1/4W 0.001

C9 0.22 R10

O2

Throttle Position

R11 1M

2

1K-1/4W

AD5-1

2

C10 0.22

Exhaust Gas Oxygen

1

1

Title Size A Date: A

B

C

Megasquirt - Input Document Number Rev 3.00 Sunday, April 17, 2005 D

Rev 3.0 Sheet

2

of E

8

A

B

C

D

E

VCC

Note 2 D1 C

1

3 Zero-Crossing Setpoint R56 R46

Q23

2 2

ZTX553 3

ZTX553

47K C32

2 R44

R51 1M

0.01

+

100K 3 3

Hysteresis Adj. U7A 1

MC34072AP

D24 1N4001

R48

1K R49

100K

C

VCC

True zero-crossing detector

R42

2

100K 6 5

U7B MC34072AP 7

8

1K

Note 1: One of two possible tach input otions are enabled during PCB build-up - opto-isolated for ignition coils, or variable-reluctrance (VR) tach input for VR, Hall, and EDIS setups. To select opto-isolator tach circuit, jumper TachSelect to OptoIn and jumper Tsel to OptoOut. For VR tach circuit (non-invert) jumper TachSelect to VrIn and jumper Tsel to VrOut. For inverted VR tach signaling, jumper VrOutInv to Tsel.

100K

R50

VCC 2

VCC

1K

4

C31 0.22

100K

1

R47

1K-1/4W

R52 1

R54

A

1K-1/4W

10K

Q22

2

1 Jmp

Jmp

R53

1

R45

3

3

VrIn

1

4N25

4

Jmp Tach Input Select

IRQ-1

Jmp

VrOutInv

Opto-isolator VCC

1

Jmp

U3

+

Note 1

Ed C12 0.001

Jmp

Opto-return Jumper Note 4

TachSelect

1

C11 0.01

4

Tsel

2

Jmp

R12 390-1/2W Dave C30 0.22

XG1

1

1

C 1N4001 John

8

XG2

TachIn

A

1N4001 Wing

Jmp VrOut

1

A

1 Jmp

4.7K

Note 3 D2

3

OptoIn

1

-

4

Note 1

OptoOut

R13

R55 1K

Note 2: Diode D1 may not be needed with hall sensor (operating at 5 volts) - install jumper in its place. 1

Note 3: Diode D2 is normally a 1N4001 installed to add an additional 0.7V forward series voltage drop (i.e. D1 + D2 + Vf_opto_diode = 0.7 + 0.7 + 1.2 = 2.6V). For hall sensor use, install jumper in place of diode. To use in ignition coil primary flyback pulse detection trigger, replace with 24V zener (connected in reverse, operate in avalanche mode), eliminate C30, and lower C12 value to 470pf. Note 4: Jumper locations XG1 and XG2 normally jumpered. For extreme ignition coil noise, XG1 can be grounded directly to engine via external connection. XG1 can also be used for Hall sensor open-collector operation.

1

Title Size A Date:

A

B

C

Megasquirt - Tach Input Document Number Rev 3,00 Sunday, April 17, 2005 D

Rev 3.0 Sheet

3

of E

8

B

C

D

V12 C

3

A

C

A

R15

10K

36V

INJ-1

3 4

NC

InputA

OutA

VSS

VDD

InputB

OutB

2

1

8

3

1 Jmp

1

R37

7

V12

0.050-TO220

6

D17 1N5819

5

R31 270-1/4W

I_INJ1

2

2

NC

Note 1

Q14 2N3904BU

A

1

Note 3

R30 270-1/4W

3 C

U4

4

D6

1

10K

PWM1-1

Q1 IRFIZ34N

22-1/4W

R17

PWM0-1

1

R32 1K-1/4W

3

R14

3

Q3 TIP42

FR302

2

Q9 TIP125

1

4.7

D3 1N4001

A

36V

+ C14

A

C13 0.1

2

D21

2

VCC

3

4

Note 2

R18 270

D5 C

E

C

A

fb_inj1

3

Q10 2N3904BU

IXDI404PI R33 270-1/4W C

Note 2

Q11 TIP42

1

D20

2

FR302

C

D7

3

A

36V A

INJ-2

1

1

3

Note 3: Flyback PWM damping circuit. Curcuit can be omitted if PWM current limiting not used.

V12

Q12 TIP125

R36 1K-1/4W 2

fb_inj2

Q13 2N3904BU 1

Title Size A Date:

C

2

1

0.050-TO220

Note 2: Active flyback clamp circuit. If using avalanche-rated FETs for Q1/Q5 then circuit can be omitted. Clamp voltage equals zener avalanche voltage.

B

R35 270-1/4W

Jmp I_INJ2 R38

3

1

Note 1: Current limit circuit for driver FET protection. Clamp current set to ~14 amps. Circuit can be omitted if protection is not required or desired - in this case install jumper in place of R37 and R38

A

Note 3

270-1/4W

Note 1 2

A

D18 1N5819

Q15 2N3904BU 1

C

3

3

R34

2

1

R20 22-1/4W

Q5 IRFIZ34N

2

2

Megasquirt - Output Injector Document Number Rev 3.0 Sunday, April 17, 2005 D

Rev 3.0 Sheet

4

of E

8

A

B

C

D

E

4

4

Note 1

IgbtOut 1

2

Jmp

IgbtIn

Q16 VB921ZVFI

1 3

1 Jmp R57 47K

R43 3

3

0.01-2W High-Current Ignition Driver

2

2

2

C

1

Q20 2N3904BU

22V 1W

D8 22V 1W

R39 1-1/2W

1-1/2W

A

R40

1K

3

D4

2

Q4 ZTX450

2

1

1

Q19 2N3904BU

1

3

1K

R19 Idle-1

C

Q2 ZTX450

2

A

R16 FP-1

3

IDL

3

FP1

Idle-Air Solenoid/Spare Drive

Fuel-pump Drive 1

1

Title Note 1: High-power ignition drive, optional circuit - populate only if implementing drive.

Size A Date:

A

B

C

Megasquirt - Output Other Document Number Rev 2.2 Sunday, April 17, 2005 D

Rev 3.0 Sheet

5

of E

8

A

B

C

D

E

D9

0.001

1N4001

1N4001

22V 1W

A A

MOV1

D12

ERZ-V20D220

+ C16 33

1N4001

U5 LM2937ET-5.0 VIN

VOUT GND

D11

1

A

C15

5 Volt Regulator

VCC

A

F1 Polyfuse RXE050

Sanctioned 5V S5 1 Jmp

3 + C17 33

C18 0.1

1

S5. Jmp

1

S5.. Jmp

2

C

12 RAW

4

Sanctioned 12V S12 1 Jmp D10 A C

12V for MSII Stepper S12C 1 Jmp C

V12

C

D13

Perry

4

C

C

12V 1W D19

A

5.6V 1W

L1

3

1uh

CGMXFC-1

R21

C19

C21

.033

.01

L2

Vref

1uh 2

OSC2-1

OSC1-1

R22

C23

C24

100K R23 10M

Y1

VDDSYN

0.1

C20

10K

3

Vsyn

0.1

+ C22

Analog

4.7

2

50 pf

32.768 KHz

C25

Sanctioned Gnd SG 1 Jmp

20 pf

CPU Clock

1

SG. Jmp

1

SG.. Jmp

1

1

Title Size A Date: A

B

C

Megasquirt - Power Document Number Rev 2.2 Sunday, April 17, 2005 D

Rev 3.0 Sheet

6

of E

8

A

B

VCC

R24 D14

330-1/4W

4

D15

330-1/4W

3

R27

Q7 2N3904BU

2 1K

1

Warmup-1

1

1K

Warm-up

1

Injector Pulse Q6 2N3904BU

2

Squirt-1

LED

3

1

LED

R26

E

R25

2

4

D

2

VCC

C

3

3

R28 2

VCC

D16

330-1/2W

R29

Q8 2N3904BU

1K

2

1

2

Accel-1

Accel Shot

3

1

LED

2

1

1

Title Size A Date: A

B

C

MegaSquirt - LED Indicators Document Number Rev 2.2 Sunday, April 17, 2005 D

Rev 3.0 Sheet

7

of E

8

A

B

C

U6 2 C27

3 4

0.1 C28

TXD-1

C29 0.1

RXD-1

5 6

0.1

7 8

C1+

5 9 4 8 3 7 2 6 1

V+ C1-

T1OUT

C2+

R1IN

C2-

R1OUT

V-

T1IN

T2OUT

T2IN

R2IN

GND

1

4

Vdd

C26 0.1

R2OUT

14 13 12 11

E

Note 1: For MS-II implementation, the following connector signal jumpers are suggested: CPU - Connector - Description ------------------------------------------------JS0 - IAC1A - Stepper motor signal 1A JS1 - IAC1B - Stepper motor signal 1B JS2 - IAC2A - Stepper motor signal 2A JS3 - IAC2B - Stepper motor signal 2B JS10 - IGN - Ignition output

VCC

16

VCC

D

P1

4

CONNECTOR DB9

10

CTS

9

1 Jmp

15

MAX232CPE

RTS

3

3

1 Jmp

MATCLT TPS O2 TachIn

12 RAW

IGN

Jmp

Jmp

IDL

1

Jmp

IAC2B

INJ-1

INJ-2

FP1

2

1 20 2 21 3 22 4 23 5 24 6 25 7 26 8 27 9 28 10 29 11 30 12 31 13 32 14 33 15 34 16 35 17 36 18 37 19

1

1

1

1

2

Spare Signals Jmp Jmp Jmp Jmp SPR1 SPR2 SPR3 SPR4

IAC2A

1

Jmp 1

Jmp

IAC1B

1

IAC1A

F2 Polyfuse RXE050

1

Vref

1

1

Title

P2 DB37

Size A Date:

A

B

C

Megasquirt - Connector Document Number Rev 2.2 Sunday, April 17, 2005 D

Rev 3.0 Sheet

8

of E

8