Doorgaan naar hoofdcontent

wiznet W7500P cortex M0 circuit board and FreeRTOS 9.0.0rc2 working

I have made my new cortex M0 based microcontroller board operational with FreeRTOS.
The chip is a W7500P
- a cortex M0 with 16KB SRAM and 128KB Flash
- hardware tcp/ip stack incl mac/phy on board (P101G)

This chip is a single chip microcontroller/ethernet/internet IoT solution, no software TCP/IP stack that can fail or hacked. For TCP/IP buffers it has another 32KB SRAM, this can be used by 8 simultaneous TCP connections (sockets open at same time).

I like this chip because it eliminates a lot of other stuff on the board. It is fast, and has lots of IO.
I added a SD-card connector for data-logging applications.
My main application will be small measurement and control applications, adding network easily and securely, super fast bootup times (0.1 sec instead of 20 sec, no linux based board with large bodies of software)

  • ADC : 12bit, 8ch, 1Msps
  • DMA
    • 6-channel DMA controller
    • Peripheral supported: UARTs, SPIs
  • GPIO
    • 34 I/Os 
  • Debug mode
    • Serial Wire Debug (SWD)
  • Timer/PWM
    • 1 Watchdog (32-bit down-counter)
    • 4 Timers (32-bit or 16-bit down-counter)
    • 8 PWMs (32-bit counter/timers with programmable 6-bit prescaler)
  • Communication Interfaces
    • 3 UART (2 UARTs with FIFO and Flow Control, 1 simple UART)
    • 2 SPI
    • 2 I2C (Master/Slave, Fast-mode (400 kbps))
  • Crypto
    • 1 RNG (Random Number Generator): 32-bit random number
Lots of issues had to be figured out eg:
- form factor and connector locations, choice of peripherals to add to the main board
- adding of RF chokes and capacitors in both digital and analog power distribution
- design of the schematic, including choice of components, eg. RJ45 and magnetics
- some parts had to be designed (schematic and footprint)
- design of the circuit board, 4 layer board, taking into account design rules and EMI issues
- assembly of the board, including component placement and soldering

The board was designed in KiCad (

The boards were hand-soldered by me, the pitch for the W7500P is 0.4mm, that is 0.2 mm spacing between tracks.

- toolchain had to be figured out, including linking (modified LD files)
- system initialisation had to change
- clock speed, now runs at 48MHz from external crystal.
- debugging using the SWD interface, using a ST-LINK interface
- programming using ISP over serial port, the S_UART (simple uart) of the chip

After the primary tests were done and found to work, eg. webserver, led-blinky it was time to port FreeRTOS to this board.

Today the FreeRTOS 9.0.0rc2 ran without troubles.

If you want something like this too, this design can be used in your OEM product, just give me a call.


900 zei…
Hi, how can you program via ISP? how about the wiring and programmer software you use? thanks a lot

Populaire posts van deze blog

Denon DHT T100 DESIGNED TO FAIL : bad caps (ceramic caps this time)

A friend gave me a Denon DHT-T100 to look at. Do not spend much time on it.. ok. It had a problem, it started clicking and ticking after power on, and after some time. (a so called intermittent problem) Sometimes it did not tick or click, but it was basically not usable. The clicking had a sharp click in one channel and repeated after about a second, then sound recovered and it would click and drop out again. He told me, do not spend any time on it, yeah, right. ;-) like I would give up after 15 minutes. I wanted to know what was going on with this thing, I found some schematic online and started measuring the usual things. The power supply, 24V did it drop down when a tick occurred ? Difficult to find out because sometimes the thing would play for hours without a glitch. I eventually found out the 24 V PSU, the step down SMPS on board and the LDO's were all ok, all power rails remained within spec, but it still glitched sometimes. (while power was ok) I investigat

Fixed voltage on cheap buck converter (MP1584) conversion with single 0805 resistor

Everywhere I look on the Ali and Ebays I see these step down converters based on MP1584. I bought a couple and actually they are not bad at all. The output voltage is set by the trimming-resistor in the left top corner of the picture. This works OK, but.. it is dangerous because it is rather sensitive to the touch. I decided that I wanted fixed output, so I had to figure out how this thing worked. The datasheet looks like this : R1 in the datasheet is what I call "R feedback" in my image. The value of R2 is mostly 8.2K Ohm in the boards I have seen.  So to set some common values for output voltage: change R1 to 27K for 3V3 output (actually 3.4 volt, but 27K is a standard value) or change R1 to 43K0 for 5.0 Volt output. (43 K is a standard value) A standard 0805 size resistor fits precisely, how convenient ;-). Make sure the other resistor is really 8.2K because that determines the feedback ratio. This way you can not burn up your circ

Raspberry Pi, PyFace Digital, the lost documentation, I found it finally

The Raspberry PI or R-pi from  is well known these days. It is not an accident that I have one, I have been doing Linux stuff since 1991, and professionally since 1996 I can not skip over these developments, have to keep up with the new kids. :-) Times have changed, hardware has become very affordable, everybody knows the Arduino , Raspberry Pi and Beagle-Bone-Black (BBB). Not everybody knows the stuff that  aka Acme-Systems and  aka  Olimex make, so I will endorse them here. Since I am an engineer I expect to connect switches and relays to the boards and some documentation with products, not so with the " PiFace Digital " board, it comes without serious documentation, not a even the schematic. All links on their blog point nowhere. People asked them many times, yet nowhere is the schematic to be found. I finally found some info after hours of google-work, someone made a c