How to substitute 74LVCC3245?

[tonyyy]

I am trying to build a project based on this hardware but I am not able to
find the ic 74LVCC3245. I red somewhere that this one can be subsitute by an HTC but
I don't know which one and how. could you please help?


Thanks a lot

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[wp100]

Hi,

Cannot see a more available substitute, though RS, Farnells/Element14/Newark, Mouser and Digikey all stock them for around $1.

 

[tonyyy]

I am based in Italy and on RS cannot find it

 

[bigdogguru]

Farnell has several hundred in stock in your area:

Farnell/Element14 TEXAS INSTRUMENTS - SN74LVCC3245APW - TRANSCEIVER, OCTAL, SMD, TSSOP24

What microcontroller do you intend to connect the ENC28J60?

If it is a 5v device, the ENC28J60 inputs are 5v tolerant, however you could use any inexpensive 5V CMOS chips with TTL level input buffers to provide the necessary level shifting to the 5v microcontroller inputs, such as the 74HCT08 or 74ACT125.

Reference: ENC28J60 Datasheet, Section: 2.5 I/O Levels, Page: 8

The ENC28J60 is a 3.3V part; however, it was
designed to be easily integrated into 5V systems. The
SPI CS, SCK and SI inputs, as well as the RESET pin,
are all 5V tolerant. On the other hand, if the host
controller is operated at 5V, it quite likely will not be
within specifications when its SPI and interrupt inputs
are driven by the 3.3V CMOS outputs on the
ENC28J60. A unidirectional level translator would be
necessary.

An economical 74HCT08 (quad AND gate), 74ACT125
(quad 3-state buffer) or many other 5V CMOS chips
with TTL level input buffers may be used to provide the
necessary level shifting. The use of 3-state buffers
permits easy integration into systems which share the
SPI bus with other devices. Figure 2-5 and Figure 2-6
show example translation schemes.

However if the microcontroller operates below 3v, you've got another issue.


BigDog

 

[tonyyy]

Wanted to create something like this:
**broken link removed**

So the PIC i already have is a PIC18FXXX.

So an 74HCT08 should work just fine. By the way I don't see on farnell enc28j60.

How I should interface the 74HCT08 between PIC and ENC28J60. Any schematic?

Thanks a lot.

 

[bigdogguru]

Wanted to create something like this:
**broken link removed**

So the PIC i already have is a PIC18FXXX.

If the PIC18FXXX is operating at 3.3v, not need for level translation.

If it is operating at 5v, you'll need to level shift at the PIC18FXXX inputs.

By the way I don't see on farnell enc28j60.

There are ENC28J60 in several packages available in your area according to the same website:

Farnell/Element14 Prodotti trovati per “ENC28J60”

You can combine the order into one shipment.

How I should interface the 74HCT08 between PIC and ENC28J60. Any schematic?

Actually there are example schematics in the ENC28J60 Datasheet, which is why I posted the link in my previous post.

It is amazing the information one can obtain from reading a devices datasheet. :lol:



BigDog

 

[tonyyy]

I see but you know sometime i see other components in other the schematics like resistors and capacitors that are not shown
in the datasheets which seem to be very logical diagram. Because of this sometime i missed some of them
and the board didnt' work.

 

[bigdogguru]

Another under used resource, in my opinion, is the Microchip development and PICtail addon boards.

If you reference the product webpage for these on the Microchip website, you find the schematics and sample code which can easily be ported to your requirements

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If you download the User Manual for the PICDEM.net 2 Board, you'll find a schematic for a similar project as you describe:

**broken link removed**


BigDog