SN74LV8153 problem

Be sure it is not in the open collector mode. If it is then you will need a pullup resistor to pull it high.

The outsel should be high to get the part in push pull mode to drive a high on the output.

I tried that but did not work.
I am connecting the A0,A1,A2 to Vcc1 so that the address is 111, Outsel is connected to Vcc1 again, Reset is connected to a switch on the FPGA, OE is connected to Vcc1, Sout is not connected to anything. Vcc1 and Vcc2 are both given 5v from a 7805 voltage regulator. I am controlling this using an FPGA in which iits signal goes up to ~3V.
the data I am sending is

0 1 Start 1 1 1  Address 1 1 1 1 Data 1 StopBit
0 1 Start 1 1 1  Address 0 0 0 0 Data 1 StopBit

Thanks

I dont see anything wrong except that you say the FPGA only goes to approximately 3V.  Vih with a 5V Vcc should be at least 3.5V.

the rest looks Ok.

so if i power the IC from the FPGA so that everything will be powered from 3V do  you think it will work? or will i need to raise the data signal from the FPGA to 5V?

Thanks a lot for your time

That would bring it into spec.  Hopefully it would make it work.

I'll try that and tell you how it goes.

It worked great, the LEDs were connected wrong. One minor problem I noticed from the chip when using an oscilloscope is that sometimes it doesn't grasp the full data rate, any sugesstions on how to  remove that?

How to connect the MAX3232 serial output RxD, TxD on SN74LV8153, only directly connect TxD on pin 5?

Or need some modification, I need to convert RS232 signal to print to an Epson tmu_295 parallel port, and I hope to serve this application
Thanks for all

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Hi Noel (or anybody)

Can you let me know if you have any code examples to program this chip?

I am using C# sending byte chunks to the port but I can't fathom out how to present the data to the chip to make it work.

I send 255 (11111111) at the start to ensure we start high, then as with your example above, I have an address of 111 and if I want all outputs to be low I send...

01 111 0000 1 01 111 0000 1

i.e Start, addr, data, stop, start, addr, data, stop

The library I am using to send data to the serial port sends in bytes, so I send the following

01111000 = 120

01011110 = 94

00010000 = 16

i.e.

Byte[] txByte {255,120, 94,16}

myFtdiDevice.Write( txByte, txByte.Count(), ref numBytesWritten );

It doesn't work so I am guessing I am doing something wrong or have the bits the wrong way around?

Any help would be appreciated.

Many thanks

Mark.

Hi Mark,

The problem that I had with it was that I left data port to '0' when not in use which did not work. The solution then is to leave data high '1' even when not transmitting data and with that the chip was working great.

Sorry I cannot offer some code because I developed the program in VHDL. Hope this was helpful.

Regards,

Noel