A

B

C

D

E

fb_inj1

4

4

fb_inj2

JS6 Jmp

1

JS7 Jmp

1

Vsyn

1

CGMXFC-1 OSC2-1 OSC1-1

1

JS0 Jmp

1

JS1 Jmp

1

JS2 Jmp

1

JS3 Jmp

U1

3

JS8 Jmp JS9 Jmp JS10 Jmp

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

1

TXD-1 RXD-1

1

IRQ-1 JS11 Jmp

2

JS12 Jmp

1

1

R1

C1 VCC

10K

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

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

3

Idle-1 FP-1 Vref AD5-1 AD4-1

1

JS4 Jmp

1

JS5 Jmp

AD3-1 AD2-1 AD1-1 AD0-1 PWM1-1 PWM0-1

2

68HC908GP32 CPU (or MS-II Daughtercard)

1

Note 6 11 16 17 18 35 36 37 38 -

1: For MS-II daughtercard implementation, the following signals apply to DIP-40 socket: CANHout CANLout V12 for IAC stepper IGN Knk Window IAC2B IAC2A IAC1B IAC1A

1

Title Megasquirt - CPU - B. A. Bowling Size A

Note 2: Jumper location JS9 (pin 16) tied to +12V for MS-II CPU board implementation for enabling IAC stepper driver.

Date: A

B

C

Document Number Rev 3.57M - SMD Monday, February 19, 2007 D

Rev 3.57 Sheet

1

of E

8

A

B

C

D

E

R2 Vref

AD0-1 C2 0.22

C3 0.1

3

1K-1/4W MAP1

Vout

V12

Manifold Absolute Pressure

Vcc

4

4

1 Vref

MPX4250AP

2

Gnd R3 50K

R4 R5

2.49K-1/4W AD1-1

MAT

C4 2.2K-1/4W 0.001

AD4-1

C5 1.0 R6 10K

Manifold Air Temp

Bootloader Entry H1

R7 R8 3

CLT

2.49K-1/4W

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

1 2 Header

C7 1.0

3

Battery Voltage Coolant Temp

R9 TPS

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

C9 0.22 R10

Throttle Position

O2

AD5-1 R11

1K-1/4W

1M

2

2

C10 0.22

Exhaust Gas Oxygen

1

1

Title Megasquirt - Input Size A Date: A

B

C

Document Number Rev 3.57M - SMD Monday, February 19, 2007 D

Rev 3.57 Sheet

2

of E

8

A

B

C

D

E

VCC R13 Note 1 4.7K Note 2 D1

4

Note 3 D2

A

C

A

C R12

OptoIn

1N4001 Wing

1N4001 John

1

2

1

Jmp

VrOutInv

R52 1

1

8

PZT2907AT1

R51 1M

1

2

-

4

1 MC34072DR2

R48 D24 1N4001

1K R49

100K

C

VCC

100K

R50

VCC 2

+

A

0.01

U7A

3

R44

C31 0.22

2

3

Hysteresis Adj.

PZT2907AT1

47K C32

3

1K Q23

2 3

100K

VCC

1

R47

10K Q22

3

100K

2

3 2

R46

R54

True zero-crossing detector

2

100K

4

R42

U7B

1K

6

-

1

Zero-Crossing Setpoint R56

1K-1/4W

IRQ-1

R53

3

1K-1/4W

4

VCC

Note 1

R45

Tsel

2 4 6

2 4 6

4N25S

Opto-isolator

Tach Input Select

Vrin

1 3 5

U3

1

2

Ed C12 0.001

Jmp

Opto-return Jumper Note 4

3

JP1

3

R57 1K-1/4W

TachIn

XG1

1 3 5

VrOut

C11 0.01

390-1/2W Dave C30 0.22

VCC XG2

J1

OptoOut

7 +

5

8

MC34072DR2

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.

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.

1

Title Megasquirt - Tach Input

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.

Size A Date:

A

B

C

Document Number Rev 3.57M - SMD Monday, February 19, 2007 D

Rev 3.57 Sheet

3

of E

8

A

B

C

D

E

V12

C

D21

C13 0.1

+ C14

36V

Q3 TIP42

FR302

D3 1N4001

1

4.7

36V

R14

A

A

INJ-1 Q1 IRFIZ34N

4

D6

2

VCC

2

4

C

A

3

A

C

C

Note 2

R18 270

D5

R15 10K

1

2

Note 1

Q14 IXDI404SI

3

1

MMBT3904LT1

Jmp

1 OutA

7

VSS

VDD

6

InputB

OutB

5

V12

0.050-TO220

3 Q9 TIP125

3

Q10 MMBT3904LT1

A

D7

R33 270-1/4W

C

Note 2

3

HS HS HS 9 10 13

fb_inj1

HS HS

4 PWM1-1

D17 1N5819

11 12

3

R32 1K-1/4W

2

InputA

1 R37

A

PWM0-1

8

1

2

3

NC

NC

Q11 TIP42

1

D20

2

FR302

C

1

R31 270-1/4W

I_INJ1

2

U4

C

10K

3

R17

Note 3

R30 270-1/4W

3

22-1/4W

36V

2

2

Q5 IRFIZ34N

A

INJ-2

2

R20 22-1/4W Note 3

1

3

R35 270-1/4W

1

0.050-TO220

V12

R36 1K-1/4W

2

Jmp I_INJ2 R38

3 Q12 TIP125

1

1

A 1

270-1/4W

Note 1

3

1

D18 1N5819

Q15 MMBT3904LT1

2

C

2

3

R34

fb_inj2

Q13 MMBT3904LT1

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

1

Title 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.

Megasquirt - Output Injector Size A

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

Date: A

B

C

Document Number Rev 3.57M - SMD Monday, February 19, 2007 D

Rev 3.57 Sheet

4

of E

8

A

B

C

D

E

4

4

Note 1

2

IG_Out

IgbtIn

Q16 VB921ZVFI

1 3

1 Jmp High-Current Ignition Driver

3

3

U8 1

SOURCE1

DRAIN1

8

2

INPUT1

DRAIN1

7

3

SOURCE2

DRAIN2

6

DRAIN2

5

R16 FP-1 1K 2

R19

4

Idle-1 1K

INPUT2

FP1 Fuel-pump Drive

2

IDL Idle-Air Solenoid/Spare Drive

VNS3NV04D-E D22

A

C

12 RAW

1N4001

1

1

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

Size A Date:

A

B

C

Document Number Rev 3.57M - SMD Friday, February 09, 2007 D

Rev 3.57 Sheet

5

of E

8

A

B

C

D

E

D9 12V for MSII Stepper S12C 1 Jmp

D11

D12

1N4001

+ C16

0.001

A A

MOV1

22V 1W

ERZ-V20D220

A

1N4001

1N4001

33

F1 Polyfuse RXE050

U5 LM2937ET-5.0

VIN

VOUT GND

C15

5 Volt Regulator

1

C

C

12 RAW

4

X_12

VCC

A

Sanctioned 5V S5 1 Jmp

3 + C17 33

C18 0.1

1

S5. Jmp

1

S5.. Jmp

2

V12 Sanctioned 12V S12 1 Jmp D10 A C

C

4

D13 Perry

C

C

12V 1W D19

A

5.6V 1W

L1

3

3

Vsyn 1uh C19 VDDSYN 0.1 R21

C20

CGMXFC-1 10K

.033 C21 L2

.01

Vref 1uh + C22 C23

2

R22

C24

0.1

OSC2-1 100K R23 10M

Analog

2

4.7

50 pf

Y1 32.768 KHz

C25 Sanctioned Gnd SG 1 Jmp

OSC1-1 20 pf CPU Clock

1

SG. Jmp

1

SG.. Jmp

1

1

Title Megasquirt - Power Size A Date: A

B

C

Document Number Rev 3.57M - SMD Monday, February 19, 2007 D

Rev 3.57 Sheet

6

of E

8

A

B

C

D

E

4

4

VCC

VCC

330-1/4W

VCC

1 1K

3

1

1

1K

Q7 MMBT3904LT1

3 Warmup-1

R59 1K-1/4W PAD2 1 1

2

1

Warm-up

R27 Q6 MMBT3904LT1

3

Squirt-1

D15 LED

R58 1K-1/4W PAD1 1 1

2

R26 3

VCC

330-1/4W

D14 LED

Injector Pulse

2

R25

2

R24

VCC R28 1-PIN PAD

2 R29

1

1

2

PAD5

1

1K

R60 1K-1/4W PAD3 1 1

Q8 MMBT3904LT1

3

Accel-1

PAD4

2

Accel Shot

1

LED 2

VCC

1

VCC D16

1

330-1/2W

1

1

Title MegaSquirt - LED Indicators Size A Date: A

B

C

Document Number Rev 3.57M - SMD Monday, February 19, 2007 D

Rev 3.57 Sheet

7

of E

8

A

B

C

C26 0.1

U6

C27

2

V+

3

C1-

T1OUT

14

4

C2+

R1IN

13

C2-

R1OUT

12

5

0.1 TXD-1

C29 0.1

RXD-1

6

V-

T1IN

11

7

T2OUT

T2IN

10

R2IN

R2OUT

15

8

5 9 4 8 3 7 2 6 1

Vdd

C1+

0.1 C28

P1

1

GND

4

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

PAD22

1

PAD23

1

1

CTS

9

1-PIN PAD

1

PAD21

Jmp

MAX232ID

1

1

RTS Jmp

MAT CLT TPS O2 TachIn

12 RAW

Jmp

IG_Out

Jmp

IDL

INJ-1

INJ-2

FP1

1

PAD6

1

1

PAD7

1

1

PAD8

1

1

PAD9

1

1

PAD10

1

1

PAD11

1

1

PAD12

1

1

PAD13

1

1

PAD14

1

1

PAD15

1

1

PAD16

1

1

PAD17

1

1

X_12

VCC

P3

8 15 7 14 6 13 5 12 4 11 3 10 2 9 1

2

CONNECTOR DB15

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

Spare Signals Jmp Jmp Jmp Jmp SPR1 SPR2 SPR3 SPR4

1

1

PAD20

IAC2B

1

Jmp

1

Jmp

IAC2A

1

F2 Polyfuse RXE050

IAC1B

1

IAC1A

3

1-PIN PAD

1

2

1 1-PIN PAD

CONNECTOR DB9

3

Vref

4

1

1

Title P2

Megasquirt - Connector

DB37

Size A Date:

A

B

C

Document Number Rev 3.57M - SMD Monday, February 19, 2007 D

Rev 3.57 Sheet

8

of E

8