Tag Archives: stm32f407

Evaluation of circuit tree with a stm32f407 microcontroller board -Part2

Design Goal

Time for another test of capability. These tests help us check the hardware compiler performance to a actual built commercial board. Some of the items for us to check are:

  1. How closer are we able to design the board with respect to requirements?
  2. Is there any possibility of optimization among circuit tree outputs?
  3. What is the board cost compared to the comparison board?
  4. Circuit Tree designs would be different than the designed board. How do we verify the design?

Olimex board

This time we compare the capability of circuit tree with another commercial board in the market available from olimex. It is a great open source hardware board available at a competitive price with great support from olimex.

Let us again pick the requirement of the board from site :

  1. STM32F407ZGT6 microcontroller
  2. JTAG connector with ARM 2×10 pin layout for programming/debugging
  3. Ethernet 100Mbit
  4. UEXT connector (UEXT is a board to board connector which supports three serial communication interfaces – I2C, SPI and RS232. There is also 3.3V line and GND.)
  5. USB host
  6. USB OTG
  7. SD-card
  8. Input DC DC power supply which allows operation from 6-16VDC source
  9. Power and user LEDs
  10. Reset and user buttons
  11. 4 full 20-pin Ports with the external memory bus for add-on modules
  12. Arduino platform with unsoldered headers
  13. 4 rubber pads for the mount holes
  14. PCB: FR-4, 1.5 mm (0.062″), soldermask, silkscreen component print
  15. Dimensions: 101.6 x 86mm (4 x 3.4″)
  16. Boards costs 40USD in quantity of unit 1 as per olimex.

Requirement entry in Circuit Tree

Let us add this requirement on circuit tree requirement editor:

Step 1:

We add requirements in the tool by adding spi, i2c and other buses to a UEXT connector. Similarily for the Arduino connector the spi and uart bus signals are routed to the connectors. We additionally add the GPIO connector having close to 11 pins. Additional interfaces such as ethernet with lan8710, usb type AB port with esd protection, sd card and jtag ports are added as per the snapshots below.






























Step 2:

Circuit Tree hardware compiler next finds the controller which can support these function. Circuit Tree returns close to 186 parts. We have option to select STM32F407ZGT6 or STM32F407ZET6 with several other parts. We choose STM32F407ZET6 as olimex schematic has this part designed into it.












We next select power of 6V to 14V as required in the requirement and get the schematic design generated in a minutes time. You would notice that the BOM cost derived from Octopart comes to USD 51. The pdf, bom and eagle schematic design is available at link













We select a board size of 130mm x64 mm.


















Output placement file is shown below with the constraint that all components be placed on the top side of the board. The red color denotes the placement of the component on the top side of the board. We need to work more on the board by adding the constraints to the board footprints. The arduino connectors are misplaced in the picture below. Files are uploaded at link










Comparison between two designs:

  1. SDHC section visual check: Circuit tree auto creates processor symbol based on the bus sections and adds them to the connector page. All pins of the connector and the processor pins are the same for sections stated below:
micro sd check

micro sd interface check










  1. JTAG section visual check:
Jtag connection visual chec

Jtag connection visual check








  1. USB section visual check: Two usb otg ports are compared. The connector pinouts, vbus generators and esd connections can be checked in the schematic.















  1. Ethernet RMII section: Comparison of lan8710 and STM32F407ZET6 connections are done. All controllers pins are the same except for the PG11 which in case of circuit tree schematic is PB11 which is correct as per pin mux.

lan8710 ethernet schematic

















  1. UEXT connector connections: The connections of the controller pins and the UEXT assignment is different than allocated. The connector pin definition is also different than the one desired.













  1. Other differences:
    1. Power, clock and reset generation is different in circuit tree. It shows that circuit tree can generates it own power supply connections based on what it calculates the extremes.
    2. Some of BOM parts selected by circuit tree are high is cost. One of the examples being integrated magnetics which cost close to usd 10. We would address this concern once we have sufficient parts in the library which would provide value range to the user.
    3. Arduino connectors are not compared as the pin assignment and gpio connections are not as per connector requirements even though the muxing from controller is correct. In the next release we would have new feature to change the connector pin outs.
    4. IFC pin connections failed as circuit tree does not generate a connection where it observes conflict of IO’s. The commercial schematic uses jumpers to isolate segments which we can also support at a later date.
    5. The placement of the design was not the same as the olimex board. We are in process of improving the constraint addition which would  help to create more custom designs.

It was a long post with visual comparison of the two boards. Write back to us at info@circuit-tree.com with your feature requests and suggestions.

Evaluation of circuit tree with a stm32f407 microcontroller board

Here is another capability test we wanted to conduct with the latest set of features. These tests help us check the limits to which we can test our engine check in addition to check the usability of the application.

We choose a stm32f407 reference design from STMicroelectronics for comparison as it is a complex board and our guess is that it has taken several week to design the board.

We quickly pulled in the design which we have created in our example library and selected components such as usb3317 from the usb library as our ulpi transceiver. We let circuit tree design remaining combinations for us. This is the what our design looked like in requirement editor.


Circuit tree quickly generated the design for us by doing all the complex tasks behind the scenes.

Let us compare the results. The table below shows what circuit tree could achieve in comparison with the board and what it could not.

Comparison chart

Comparison chart of features supported by the two boards

I am glad to report following findings:
1. Circuit tree did not connect two peripherals in parallel. For instance MicroSD connector and RS232 connectors. It also did not do create connections where audio port is shares pin with MicroSd port ON ST boards. Here are the list of pins allocated by the circuit tree versus the application board.
2. Some of the features we don’t support at the moment but we have capability to do so and extending our capability every day.
3. Finding processor pins for the peripherals, component selection for peripherals, power clock reset, optimisation, decision circuit configuration , schematic generation and check is all done in a shortest span of time. We like to keep things simple and easily understandable for our users which is reflected in our final output.
4. The application schematic generated can still be downloaded in a popular PCB design tool and used for further customisation.
5. The best part is that I can quickly go back to the requirement editor and change
a). The ethernet transceiver to Microchip lan8710 and
b). The CAN transceiver to TI SN65HVD230D and
c). Change zigbee module to Zigbee Internation XB24C module.
d). change input voltage to 9V.

The design file [containing Eagle and Altium] Schematic and the bill of material  is ready by the time i write this. You can check it out through the link below:


TIP: You could also go back to the board requirement menu ,delete the processor and add any other processor and still generate the design.


Short Introduction to Circuit tree

Circuit tree is a online EDA application having intelligence of a hardware engineer to create embedded hardware designs. It features more than 1000+ processors and controllers along with extended hardware peripheral library.

Here is a introduction video to circuit tree:

Schematic Pages of interest you should visit when using Circuit tree application


Circuit tree is a online platform to generate a embedded design schematic and PCB placement using a easy to use editor with online library components. The  hardware compiler generates the design in  minutes and we have used the platform to generate thousands of designs and schematics. Whenever a schematic is generated for a given set of requirements, the application output always surprises and baffles us with something new. We get excited to see the generated output as we in no way control

  1. Component selection unless pre-selected from requirement page.
  2. Pin mux selection of the processor
  3. Power and its sequencing, clock, reset generation on the board
  4. Schematic Symbol generation
  5. Circuit connections on board
  6. Schematic Page creation.

This is the amount of variability the application has. This unconstrained output is however tested thoroughly before the schematic is displayed.

Continuing with the above thought we would like to share some of the most dynamic schematic connections generated so that you can understand that each created design is unique and the effort we have invested to ensure that the designs delivered to you are correct.

Use Cases

For this discussion we will be using the hardware compilers and its library components.

  1. When visiting stm32f407 look out how the usb connections are generated. Some of the requirements pictures are posted below in the figure. Also you can select ulpi and try exploring these pages too.

    USB requirement for stm32f407

    USB requirement for stm32f407

  2. When using imx6 controller select rgmii/rmii/mii interface in ethernet  or try pcie implementation. Look how the power sequencing takes places when rgmii phy with two power up voltage steps and imx6 with four power up ramp up steps ramp with with the  remaining circuit.
  3. When using the atmel same70 controller check how the usb connections vary based on the host or device requirement. Here is the final twister. Atmel microcontrollers requires that vddio supply should be above 3.0V when usb connections are being used. Use the atmel_same70q_example1 to commit requirement when
    1. Usb block is present
    2. Usb block is deleted from the requirement page


There are lot more interesting ways in which the circuit changes and we enjoy exploring these creations. Keep exploring and don’t forget to share your feedback about the application.

Need More

We have many more designs to prove that the circuit tree hardware compiler out there. Visit our github directory to know more about the automated design deliverables.