Switches & LEDs PE[06..15] Port E K400

1

2. Board description

2.1. The block diagram

The circuit consists of ten blocks depicted in Fig. 1. Each block is later represented by one page of

schematic diagram. The central block represents the microcontroller STM32F407VE, housed in LQPF

package with 100 pins. Port pins are used to connect the microcontroller with other blocks. All blocks

have connectors for external signals, these connectors are distributed along edges of the board for

easy access. The power supply is common for all blocks.

Figure 1: The block diagram of the STM32F407 board. Boxes with thich borders are blocks, boxes with thin borders

are connectors.

PA[00..03]

PA[04..05]K300

Serial bussesPB[06..07]

PB[08..09]

PB[11..10]

PB[02..05]

PB[12..15]

K460

K465

K470

K480

K485

I2C1 & USART1

I2C1 & CAN1

I2Cs & USART3

SPI1 & SPI3

SPI2 & CAN2

U300, U310

U320

Analog interface

Digital IOPD[00..07]

PE[06..15]

K450

K400

K440

K451

Port D

Port E

MOSFETs

PD[08,09]

PC[10,11]

PE[00..05]

Power output

RS232 - 12V

RS232 - USB

Switches & LEDs

K500

J550

K505

P580

K510PD[12..15]

PC[06..09]

PC[12]

PD[11]

U500

U505

U550

U580 U100

PC[00,05]K350

LCD

P350

J370PA[06,07]

PC[13]

PD[10]

D390 - D393

S370 - S375

K190 K120SWD USB - OTG

B200

B201

+12V

GND

Microcontroller

Power supply

U200, U210

U230

Playing with STM32F407 test board – board description

2

2.2. The power supply

The board needs +3.3 V power supply for the microcontroller and its peripheral circuits and +5 V

for the LCD display. Additionally, the analog electronic circuits in front of the ADC and output buffers

for the DAC might need ±5 V power. The power supply circuit provides all required voltages. It

consists of three sub-blocks and two headers as shown in Fig. 2.

The circuit is powered through connectors B200 (+12VIN) and B201 (GND). The voltage applied

between these two connectors can range from 7 V DC to 25 V DC (nominally 12 V DC), and is used by

the first block built with voltage regulator U200 to provide local +5VD. The rest of the microcontroller

circuit can be powered from this +5VD but can also be powered from +5V obtained through a USB

connector plugged into a PC compatible computer. The user can select either using a jumper J205.

The required current from either source depends strongly on the microcontroller current

consumption (about 100 mA) and the current consumption of peripheral circuits (depends…). It is

expected that 500 mA should suffice for the microcontroller board.

Voltage regulator U210 is used to reduce the +5V into +3.3V for the microcontroller, and

switching regulator U230 is used to transform +5V into ±5V for the analog part of the circuit.

The motor driver requires more than 5 V, and can be powered from B200 directly if a jumper is

inserted into the header J220 between pins 2 and 3. Alternatively, the jumper can be removed and

external power supply can be applied to header J220 between pins 3 and 1.

The complete schematic diagram of the power supply is given in Fig. 9. Capacitors shown at the

schematic are used for decoupling of the power supplies and are distributed along the power lines on

the board, mostly around the microcontroller. All three power supplies are also connected to three

green LEDs (D240, D241 and D242) to confirm the validity of power supply lines. All headers /

jumpers in the power supply lines can also be used to connect an instrument to measure the current

consumption.

2.3. The microcontroller

The microcontroller STM32F407 connects to the world using four 16 bit ports (PA, PB, PD and PE)

and one 14 bit port (PC). It requires a power supply of 3.3V for digital circuitry and a separate +3.3V

Figure 2: Block diagram of the power supply

J205

123

J2201 2 3

B200

B201

+12V

GNDU200 U210

U230

+5VD

+5V from USB

+5VA

-5VA

+3V3

+12V

+5VPower input

header / jumper

header / jumper

to be used on-board


3

power supply for analog circuits. Both can come from the same source, but the power supply for the

analog part must be additionally decoupled using inductors and combination of capacitors as shown

in Fig. 3. Digital power supply for the microcontroller is provided through several pins on the chip,

and each pin should be decoupled with a 100 nF ceramic capacitor to ground using a short

connection. This is best achieved by implementing a large ground plane on one side of the board, and

using feed-through holes to connect decoupling components to ground.

The microcontroller includes crystal oscillator circuits for two crystals (8 MHz and 32768 Hz).

Two options are available to program the microcontroller: JTAG and SWD. The board implements

only the SWD bus for programming. The SWD bus is available on header K190. The microcontroller

normally gets a reset signal through the SWD bus, local RESET pushbutton is also available (S110).

The microcontroller implements a USB “On-The-Go” bus. Its implementation is copied from the

DISCOVERY board, but with different overvoltage protection chip (SN75240). This chip might not be

the best solution, but will hopefully do its job. The USB OTG bus is available on mini USB connector

K120. Jumper J263 can be used to select the power supply on the USB-OTG connector.

The complete schematic diagram of the microcontroller is given in Fig. 10.

2.4. The analog interface

2.4.1. Input buffer for ADC The allowed range for ADC input signals is from 0

V to +3.3V, as defined by the analog power supply

for the microcontroller. An operational amplifier is

used in front of the ADC to buffer the input signal

and provides a low impedance driving required for a

high resolution ADC. The schematic diagram of a

single buffer is given in Fig. 4.

The operational amplifier in the prototype is

OPA2354, a high speed, rail-to-rail IO, +5.5 V supply,

dual amplifier. Other amplifiers will be tested in due

time. The amplifier is powered from +3.3 V and GND; this is achieved by inserting jumpers J303

and J304 (not shown in Fig. 4) in proper positions so that +VAN becomes +3.3 V and –VAN

becomes GND. Both power supply pins are decoupled by 100 nF capacitors. Since the output

Figure 3: Making of the decoupled version of the +3.3V as an analog power supply for the microcontroller

+3V3

C130100n

L130

C133100n

C1341u/5V

C135100n

L131

R133 47

C1321u/5V

ANALOG +3.3V

pin 21

pin 20

pin 22

+3.3V reference

ANALOG GND

Figure 4: The schematic diagram of the input

buffer


4

signal of the amplifier cannot go beyond the power supply lines, such selection assures the safety

of the ADC input, and no further protection is needed at the output of the operational amplifier.

The amplifier has a gain of one, giving it a bandwidth of more than 10 MHz. The input signal

AIN0 first enters the combined resistor divider (R300, R301) and RC filter (R300||R301 and C301).

A jumper J301 selects the function of the resistor divider. There are three options:

- Unipolar mode 3.3: Jumper is not inserted: In this case the input signal appears directly at

the input of the buffer, therefore 0 V DC at the input AIN0 is translated into 0 V DC at the

input of the ADC PA0, and +3.3 V DC at the input AIN0 is passed to the ADC input PA0 as

+3.3 V DC. The range of input voltages is 0 to 3.3 V.

- Unipolar mode 6.6: Jumper shorts R301 to GND: In this case the input signal is reduced to

½ before entering the buffer, therefore 0V DC at the input AIN0 translates as 0 V at the

input of the ADC, and +6.6 V DC translates as +3.3 V DC. The range of input voltages is 0 to

6.6 V.

- Bipolar mode: Jumper shorts R301 to +3.3V: In this case the input signal is reduced to ½

and bias is added to the result before entering the buffer; +3.3 V DC at the input AIN0

translates as +3.3 V DC at the input of the ADC, and -3.3 V DC at the input AIN0 translates

as 0 V DC to the input of the ADC. The range of input voltages is -3.3 to 3.3 V.

The combined resistance in the resistor divider and the capacitor C301 form a RC low pass

filter with a corner frequency of 330 kHz (660 kHz with jumper inserted). A protective diode D301

can be soldered into the circuit (see the complete schematic diagram) to clamp the input signal to

an acceptable level at the input to the operational amplifier when excessive input voltages are

applied at the input AIN0.

The output of the buffer is connected to the input of the ADC using another RC low pass filter

formed by R302 and C302. This is not really a filter; the capacitor is needed as a charge reservoir

to allow error-free sampling of the signal at the input to the ADC. A resistor R302 is added in

series to reduce capacitive loading of the operational amplifier and prevent oscillations. The

capacitor C302 is connected between the analog input pin of the microprocessor (PA0, pin 23)

and ground plane with a shortest possible wire, while the connection from operational amplifier

to resistor R302 can be longer. All analog part of the board is built with the ground plane on the

opposite side of the board.

Four such amplifiers are implemented, one for each input channel AIN0 to AIN3, see the

complete schematic diagram in Fig. xx. Some decoupling capacitors are distributed on the analog

part of the board.

The suggested operational amplifier is a Rail-to-Rail type, and its output can almost reach

power supply rail; it’s saturation voltage is about 60 mV. This means that, when unipolar mode

3.3 is selected, the ADC can measure voltages from about 60 mV to about 3.24 V. The first and the

last 60 mV cannot be measured since the operational amplifier cannot pass such signals to the

ADC. In order to avoid this situation a regular fast dual operational amplifier (initial suggestion:

AD8034) with elevated power supply voltage can be soldered in place of OPA2354, but the power

supply for it should be increased to ±5 V. Such power supply is available on the board when the

U230 is soldered into the board. Jumpers J303 and J304 must be re-inserted in correct positions.

However, increasing the power supply opens the possibility for the operational amplifier to pass

signal beyond the power supply rails of the microprocessor to the input of the ADC when un-


5

appropriate input signal is applied, and this could harm the ADC. Protective diodes D302 must be

introduced to clamp the signal to an acceptable level.

2.4.2. Output buffer for DAC.

In order to protect the microcontroller and to

increase the output current from DAC a buffer

amplifier is added in the circuit. The schematic

diagram of the buffer is shown in Fig. 5.

The output signal from DAC is between 0 V and

+3.3 V. This signal is first feed to a low pass filter

formed by resistor R320 and capacitor C320. Values of

components are selected to give the corner frequency

of about 1 MHz. Filtered signal is fed to the

operational amplifier. There are two options:

- Unipolar mode: In this mode the operational amplifier is connected to have a gain of +1,

therefore resistor R321 is not soldered into the circuit (NI, not inserted), and resistor R322

is replaced by a short circuit. The operational amplifier simply repeats the input signal. The

power supply in this mode can be either single (+3.3 V and GND) or dual (+5 V and -5 V).

Jumpers J303 and J304 select the appropriate power supply. As with the input buffer the

saturation voltage of the operational amplifier limits the output signal to a range from

about 60 mV to 3.24 V when a single supply is selected. When such limited range of output

voltages is not sufficient a dual power supply should be activated by proper selection at

jumpers. This might require a different operational amplifier. For initial testing the

operational amplifier AD8646 was used.

- Bipolar mode: In this mode both resistors R321 and R322 are soldered into the circuit. This

gives a gain of +2 to the operational amplifier and offsets the output signal for -3.3 V:

when input signal to the circuit is 0 V DC the output is -3.3 V DC. When input signal is +3.3

V DC the output signal is +3.3 V DC. In order to achieve the extended range of output

voltage the operational amplifier must be supplied by ±5 V. This power supply can be

selected by jumpers J303 and J304, as for the input buffer, and an operational amplifier

with power supply of at least ±5 C must be used.

Please bear in mind that the jumpers J303 and J304 are common for the input and output section.

A change in the position of jumpers will therefore affect both buffers and operational amplifiers must

be selected accordingly in both sections.

The output signal from the operational amplifier is fed to another low pass RC filter formed by

resistor R323 and capacitor C323. The values are selected to give the corner frequency of about 10

MHz and may change when additional tests are performed. Two such output buffers are

implemented for two DAC built into the microcontroller. The complete circuit is given in Fig. 11.

2.5. Serial buses

The microcontroller offers a wide variety of serial busses. The required hardware is built into the

microcontroller and operates without the intervention of software. The user must only initialize the

hardware and supply the data to be transmitted & intercept the received data. Lines used to

Figure 5: The schematic diagram of the output

buffer

+VAN

-VAN

+3V3A

PA04

AOUT0

R32356

R320 1k

C323220p

C320150p

-

U320AAD86462

31

84

R321 NI R322 0


6

implement serial buses are available at different ports, but this implementation reserves the port B

for serial bus connections.

An example of connection to provide a

serial bus I2C or RS232 is shown in fig. 6. Two

pins of port B (PB06, PB07) are used as

inputs/outputs for corresponding signals of a

bus; both are connected to the connector at

the edge of the board. Two small value

resistors are added in series to reduce the

possibility of a failure when connector pins are not properly connected.

Most of the devices utilizing a serial bus require a power supply, which can be provided from the

board. Jumper J460 should be used to select the appropriate voltage. Two resistors R463 and R461

are needed for proper operation of I2C bur which requires pull-up resistors. These resistors can be

omitted for RS232(TTL) bus.

A similar circuit is provided on the board

also for other bus variants, fig. 7 gives an

example for SPI bus.. Again, four resistors are

added in series with SPI lines to reduce the

possibility of damaging the microcontroller.

The power supply for the device utilizing the SPI bus can be selected by means of the jumper J485.

See Fig. 12 for other busses and the complete schematic diagram.

2.6. On-Board switches and LEDs

Six push-button switches are available on the board to allow the user interaction with the

software. Pull-down resistors are provided on the board, so the programmer does not need to

activate the pull-down resistors built in the microcontroller. This was provided for simplicity, but can

be omitted when soldering the board. The switches are connected to lower six lines of port E, and

these lines are also available at the connector J370 for the connection of an external keyboard should

this prove necessary. Protective resistors are inserted between the connector and microcontroller for

each line.

Four LEDs are available on the board. They are under program control and can be used to signal

the state of the user program. LEDs are available on pins PA06, PA07, PC13 and PD10.

The complete connection of switches and LEDs is given in Fig. 13.

2.7. Digital IO – ports

Digital lines to be used as inputs to the microcontroller or outputs from the microcontroller are

available on two connectors K400 (upper ten lines of port E, PE06 to PE15) and K440 (lower eight

lines of port D, PD00 to PD07). The digital lines are 5 V tolerant, so a signal between 0 V and +5 V can

be connected here. Each line has a current limiting resistor inserted to reduce the possibility of

damage when signals out of this range are applied.

Both connectors offer a power supply lines +3.3V and +5V to be used by the external circuits.

Figure 6: An example of I2C / RS232(TTL) bus

+3V3+5V

PB07PB06

R463 4K7

R461 4K7

R460 100

R261 100C460100n

J460K460

1 235 6

4SCL/TX V1SDA/RXG1 G2

V2

Figure 7: An example of SPI / CAN bus

+3V3+5V

PB14PB13PB12

PB15R488 100R487 100R486 100R485 100

C485100n

J485

K4851 23 45 67 8

SEL/RX V1SCK/TX V2MISO G3MOSI G4


7

Four power transistors are available on board. They are BSP296 type MOSFETs with low gate-turn-

on voltage to allow the driving from +3.3V. Four GATEs of transistors are available at connector K450,

and four drains at connector K451. Gates of transistors are terminated to ground on the board. Both

connectors also offer the power supply for external circuitry, this time +5 V and +12 V.

The complete schematic diagram for the digital IO is given in Fig. 14.

2.8. RS232 bus - ±12V

A standard RS232 bus utilizing TTL to ±12 V driver is implemented on the board. The drivers

receives support from the microcontroller, pins PC10 and PC11, and is connected to standard D9

connector P580 at the edge of the board. Caution: the connector can also supply +5 V to external

circuits at pin 9. The complete schematic diagram of the RS232 driver and connector is given in Fig.

15.

2.9. Power output – motor driver

The microcontroller cannot supply much power to the load; it can only give digital control signals.

In order to drive for instance a motor, some current is needed and this can be provided by a power

driver.

It is expected that two motors might be connected to the board simultaneously. Both motors can

be either stepper or regular type. The expected current consumption of these motors is 1 A at most,

and the maximum voltage for the motors will be up to 24 V. A standard driver chip L293 is used for

each motor. The schematic diagram for one of the chips is given in Fig. 8.

The driver chip is connected to suitable output pins of the microcontroller, which allow either the

programmatic control of the diver or, when the appropriate function is selected, the PWM control.

Pin PC12 is used to enable the driver, and its outputs are available at the connector K500. The chip

has built-in clamp diodes towards the ground and power supply. The VCC1 is connected to +5 V

assuring that the chip will correctly interpret 3.3 V signals from the microcontroller. The power

output stage is supplied by +12 V, the same as connected to B200 or connector J220, as selected by

the user. The chip is decoupled to ground using capacitor C502 (as big as possible to fit within the

space on the board and to withstand the supply voltage) and C501.

The complete schematic diagram is available in Fig. 16.

Figure 8: The schematic diagram of a motor driver

+12V

+12V

+12V+5V

PC12

PC08

PC09PC07PC06

BPC09

BPC07

BPC06

BPC08 BPC09

BPC07

BPC06

BPC08

U500L293D

27

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C501100n

C502ELC

R500100K

K500

12345678910

1112

C500100n


8

2.10. RS232 bus – USB interface

The board hosts a FTDI chip to convert between USB and RS232. The complete schematic of the

circuit is given in Fig. 17. The FTDI chip is supplied from the USB bus. It can be galvanically separated

from the microcontroller when optocouplers U555 and U556 are inserted and jumpers J554 and J557

are properly selected or connected directly to the microcontroller. Pins PD08 and PD09 are used as a

source for the microcontroller RS232 bus.


9

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Figure 9: The schematic diagram of the power supply


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TO

R1

I2C

1/U

SA

RT1

I2C

1/C

AN

1

I2C

2/U

SA

RT3

SP

I2/U

SA

RT3

SP

I1/3T

IM2

TIM

1

LED

AF1

AF10

AF1

AF5/6

AF4/7

AF4/9

AF4/7

/CA

N2

AF5/7

AF9

AF8

AF7

Figure 10: The schematic diagram of the microprocessor


11

+V

AN

+V

AN

+V

AN

-VA

N-V

AN

-VA

N

+V

AN

+V

AN

+V

AN

+V

AN

-VA

N

+5

VA

-5V

A

+3

V3

A

-VA

N-V

AN

-VA

N

-VA

N+V

AN

+V

AN

-VA

N

+3

V3

A

+3

V3

A+3

V3

A

+3

V3

A

+3

V3

A+3

V3

A

+3

V3

A

+3

V3

A+3

V3

A+3

V3

A+3

V3

A

+3

V3

A+3

V3

A+3

V3

A

+3

V3

A+3

V3

A

PA

00

PA

03

PA

02

PA

05

PA

04

PA

01

PA

00

PA

01

PA

02

PA

03

AIN

0

AIN

1

AIN

2A

2

A3

AIN

3

A2

A3

AO

UT0

AO

UT1

A0

A1

A0

A1

AO

UT0

AO

UT1

AIN

3

AIN

2

AIN

0

AIN

1

C3

03

100n

D3

06

BA

V99

R3

28

56 C

328

220p

R3

26

NI

R3

27

0

D3

11

BA

V99

D3

16

BA

V99

C3

25

150p

R3

25

1k

C3

23

220p

R3

20

1k

R3

23

56

C3

20

150p

J3

03

J3

04

-

U3

20

AA

D8

64

62 3

1

8 4

C3

21

100n

C3

04

100n

C3

02

1n

R3

02

22

C3

14

100n

-

U3

00

BO

PA

2354

6 57

C3

22

100n

R3

07

22

R3

06

10k

R3

05

10k

C3

06

47p

C3

07

1n

R3

21

NI

J3

01

J3

11

J3

16

J3

06

C3

11

47p

-

U3

10

AO

PA

2354

2 31

8 4

C3

12

1n

R3

12

22

R3

11

10k

R3

10

10k

-

U3

00

AO

PA

2354

2 31

8 4

R3

17

22

-

U3

10

BO

PA

2354

6 57

C3

17

1n

C3

16

47p

C3

24

100n

C3

29

100n

C3

26

100n

D3

01

BA

V99

R3

15

10k

R3

16

10k

C3

01

47p

C3

13

100n

R3

22

0

C3

27

100n

D3

02

BA

V99

D3

07

BA

V99

D3

12

BA

V99

D3

17

BA

V99

R3

00

10k

-

U3

20

BA

D8

64

66 5

7

R3

01

10k

K300

12

34

56

78

910

11

12

13

14

15

16

17

18

19

20

Figure 11: The schematic diagram of the analog interface


12

+3V

3+5V

+3V

3+5V

+3V

3+5V

+3V

3+5V

+3V

3+5V

PB

07

PB

06

PB

09

PB

08

PB

11

PB

10

PB

04

PB

03

PB

02

PB

05

PB

14

PB

13

PB

12

PB

15

R463

4K

7

R461

4K

7

R483

100

R482

100

R468

4K

7

R480

100

R481

100

R466

4K

7

R488

100

R487

100

R486

100

R485

100

R460

100

R261

100

R467

100

R465

100

R470

100

R472

100

R471

4K

7

R473

4K

7

C460

100n

C480

100n

C465

100n

C470

100n

C485

100n

J460

K460

12

3 564

SC

L/T

XV

1S

DA

/RX

G1

G2

V2

J480

J485

K480

12

34

56

78

SE

LV

1S

CK

V2

MIS

OG

3M

OS

IG

4

K485

12

34

56

78

SE

L/R

XV

1S

CK

/TX

V2

MIS

OG

3M

OS

IG

4

K465

12

3 564

SC

L/R

XV

1S

DA

/TX

G1

G2

V2

J465

K470

12

3 564

SC

L/T

XV

1S

DA

/RX

G1

G2

V2

J470

I2C

1 &

US

AR

T1

I2C

1 &

CA

N

I2C

2 &

US

AR

T3

SP

I1 &

SP

I3

SP

I2 &

CA

N2

AF

4A

F7

AF

4A

F9

AF

4A

F7

AF

5A

F6

AF

5A

F9

Figure 12: The schematic diagram of connections for serial buses


13

+3V

3

+3V

3

PD

10

PA

06

PC

13

PA

07

PE00

PE03

PE04

PE05

PE01

PE02

E00

E01

E02

E03

E04

E05

E05

E04

E03

E02

E00

E01

D393

RE

D

D391

RE

D

R38

51M

J370

1 2 3 4 5 6 7 8

R405

100

R404

100

R403

100

R402

100

R401

100

R400

100

D390

RE

D

R384

1M

R383

1M

R382

1M

R381

1M

R380

1M

D392

RE

D

S371

S372

S373

R393

220

R392

220

R390

220

R391

220

R370

10k

S370

S374

S375

R371

10k

R372

10k

R373

10k

R374

10k

R375

10k

Figure 13: The schematic diagram for switches, LEDs and external keyboard


14

OQ

450

OQ

451

OQ

452

OQ

453

IQ450

IQ451

IQ452

IQ453

+3V

3

+5V

+3V

3

+5V

+12V

+5V

+12V

+5V

+12V

+5V

+5V

+3V

3

+3V

3

+5V

PE07

PE09

PE11

PE15

PE13

PD

00

PD

02

PD

06

PD

04

PD

01

PD

03

PD

07

PE10

PE06

PE14

PE08

PE12

PD

05

C440

100n

C400

100n

K451

1 2 3 4 5 6 7

Q451

BS

P296

Q450

BS

P296

R406

100

R412

100

R410

100

R408

100

R414

100

R453

1M

R452

1M

C450

100n

R451

1M

C451

100n

R450

1M

R415

100

R411

100

R409

100

R407

100

R413

100

K400

12

34

56

78

910

11

12

13

14

15

16

17

18

19

20

Q453

BS

P296

Q452

BS

P296

R447

100

K450 1 2 3 4 5 6 7

R441

100

R445

100

R443

100

R440

100

R442

100

R446

100

R444

100

K440

1 2 3 4 5 6 7 8 910

11

12

13

14

15

16

17

18

PO

RT

E

PO

RT

D

Figure 14: The schematic diagram of digital IO connectors and power transistors


15

+3V

3

+5V

PC

11

PC

10

P5

80

DB

9 M

ALE

594837261

C585

100n

C582

100n

C583

100n

U580

MA

X3232

1 3 4 5

16

11

10

12 9

813

714

15

62

C1+

C1-

C2+

C2-

VC

C

TR

1_I

TR

2_I

RC

1_O

RC

2_O

RC

2_I

RC

1_I

TR

2_O

TR

1_O

GN

DV-

V+

C580

100n

C581

100n

C590

100n

R593

100

R591

220

R590

220

R592

100

J190

RS

23

2 D

RIV

ER

+/-

12

V

Figure 15: The schematic diagram of the TTL to RS232 translator


16

+5V

+12V

+12V

+12V

+12V

+12V

+12V

+5V

+3V

3

PD

11

PC

12

PC

08

PC

09

PC

07

PC

06

PD

15

PD

14

PD

13

PD

12

PD

11

PC

12

PD

14

PD

12

PD

13

PD

15

PC

07

PC

09

PC

06

PC

08

BP

D12

BP

C09

BP

C07

BP

C06

BP

C08

BP

D15

BP

D14

BP

D13

BP

C09

BP

C07

BP

C06

BP

D15

BP

D12

BP

C08

BP

D14

BP

D13

U500

L293D

2 710

15 1 9

3 6 11

14

16

8451312

1A

2A

3A

4A

1,2

EN

3,4

EN

1Y

2Y

3Y

4Y

VCC1

VCC2GNDGNDGNDGND

C502

ELC

C501

100n

R500

100K

K5

00

12

34

56

78

910

11

12 K

50

5

12

34

56

78

910

11

12

C506

100n

C507

ELC

C505

100n

R514

100

C500

100n

R519

100

R516

100

R518

100

R515

100

R517

100

R513

100

R510

100

R511

100

R512

100

K5

10

1 3 5 7 9 11

13

15

16

14

12

108642

R505

100K

U505

L293D

2 710

15 1 9

3 6 11

14

16

8451312

1A

2A

3A

4A

1,2

EN

3,4

EN

1Y

2Y

3Y

4Y

VCC1

VCC2GNDGNDGNDGND

C510

100n

ST

EP

PE

R M

OT

OR

1

ST

EP

PE

R M

OT

OR

2

TO

EX

TE

RN

AL M

OT

OR

DR

IVE

R

Figure 16: The schematic diagram for power drivers – stepper motors


17

+5

V_

US

B

+3

V3

FT

+3

V3

FT

+3

V3

+3

V3

FT

+3

V3

PD

08

PD

09

J5

57

J5

54

J5

50

US

B-B

1 32 4 5 6

Vusb

D+

D-

GN

D

SH

IELD

1S

HIE

LD

2C

553

100n

C5

50

100n

U5

50

FT2

32

RL

420

16

15

19

27

28

17

1 5 3 11

2 9 10

6 23

22

13

14

12

26

25

7 18

21

VC

CIO

VC

C

US

BD

MU

SB

DP

RE

SE

T

OS

CI

OS

CO

3V

3 O

UT

TXD

RXD

RTS

CTS

DTR

DS

RD

CD RI

CB

US

0C

BU

S1

CB

US

2C

BU

S3

CB

US

4

TE

ST

AG

ND

GN

DG

ND

GN

D

C5

51

100n

L550

R5

51

10k

R5

55

100

R5

56

100

R5

57

100

R5

52

47k

J2

R5

54

100

U5

56

HC

PL-0

61

26

3

8 57

R5

50

33k

U555

HC

PL-0

61

26

3

8 57

Figure 17: The schematic diagram of the USB to TTL-RS232 converter


18

Figure 18: Component stuffing diagram, top side


19

Figure 19: Component stuffing diagram, bottom side


20

Figure 20: Board layout, top layer


21

Figure 21: Board layout, bottom layer, mirrored


22

Figure 22: Signal & connector layout


23

Figure 23: Photo of the assembled board, top view, not finished

Documents

Switches & LEDs PE[06..15] Port E K400