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Components used on FEZ Cerbuino NET


#1

I’m having trouble identifying some of the components on Fez Cerbuino NET, since I’m considering a design based on the STM32F40.

The parts that are not clear to me are:

Y1: CrystalHC49UP
X7: CrystalSM49
L2: FB

I have no idea wat type of component L2 is. According to the schematic it’s a resistor, but I can’t understand the value.

If someone could supply digi/newark/mouser partnumber that would be awesome.

Thanks!


#2

Generally speaking, L stands for inductor, FB stands for ferrite beads. I don’t have access to eagle schematics right now but I am quite sure the components are:

  1. crystal, HC49 package, value in term of Hz should be on the schematic
    2)crystal, SM49, this is most likely a surface mount, again frequency can be found on schematics.
  2. a ferrite bead, choke, used to suppress EMI. The most importance property, resistance at 100Mhz should be on the schematics too. I bet it is 600ohm at 100Mhz.

Hope this helps.


#3

Hi Jerome,

I started out with downloading the schematics as a reference. For all components the value has been given, except for these three. Hency my question. :wink:

In the the datasheet for the ENC28J60 there is written:
The ENC28J60 is designed to operate at 25 MHz with a crystal connected to the OSC1 and OSC2 pins. The ENC28J60 design requires the use of a parallel cut crystal.
So the requency for that one is clear, but I don’t understand what they mean with parallel cut crystal.

The datasheet for the STM is more vague about the crystal; it can be between 4 and 26 Mhz, but since I plan to use the same firmware as beeing used on the Cerb.net, I guess I need the same frequency. The crystal on the Cerb I own is marked U12.000 C01J. Does this mean that it’s 12Mhz?

Since L2 is in a 0603 package, I can’t read anything of it.

To be on the safe side, it would be great if someone from GHI could provide partnumbers or specifications for these components.

Thanks for your help so far.


#4

L1 - something like this (0805):

http://www2.mouser.com/ProductDetail/Murata/BLM21BB600SH1D/?qs=%2Fha2pyFadugFWMmcnfWvP0utw1LhksDrNnRNv6%2bn6hByYDnU4oaNEw%3D%3D


#5

The link is hidden…


#6

@ NickS -

From the eagle files I just downloaded from GHI, Y1, the crystal connected to ENC28J60, the value reads 25MHz.

As to the crystal connected to STM32F4, if you are going to use cerb firmware, the value should be 12MHz. From my understanding, you can simply use any 12Mhz crystal, at least that’s what I did and it worked.

I can see something is in the value field of L1, but it is all question mark, so I guess this is a coding page thing. sorry I cannot help you on this one.


#7

Thanks for all the replies. I will order 25Mhz and 12 Mhz Crystals.
For L1 I will order the suggested bead and see how it goes.

I will let you know if it works.


#8

Last week my PCB’s arrived and after some fiddling with soldering the STM, everything worked as expected.

So, for anyone interested:
X1: ABLS-12.000MHZ-B2-T
Y1: ABLS-25.000MHZ-B2F-T
L1: BLM21BB600SH1D

Thanks for all the support.


#9

Nice! Show us some pictures of your board if you don’t mind.


#10

Sure! Image is attached.

One of my first MF projects was a pager server to send messages to old-style telecom pagers.
It uses a VHF transmitter to actually send the mesasages and I used chipworkx to create the POCSAG messages, calculate checksum and bit-bang them to the transmitter.
On this board, there are inputs for 10 buttons. When a button is pressed, a pre-programmed message is send to one or more pagers. I have about 40 boards running in several situations, for more than two years now without any problems!

For a new client, this set-up is to be used in an hospital, but this requires much more buttons in the entire building.
For this purpose, I have created this slave board, which will send messages over TCP to the pager server. The pagerslave has inputs for 5 buttons and outputs for 5 indicators.These will be mounted at bedside which reduces the amount of cabling required.
The whole thing is powered over ethernet by using an external POE adapter.


#11

Very nice!


#12

Thanks! :slight_smile:


#13

Good to see another board in the wild - nice one :slight_smile:


#14

@ Bill Gates - Thanks! It was much easier than I expected.