ST7540 Power Line communication IC

H

hayowazzup

New Member

• Jul 21, 2012

• #1

Hi all

I am using st7540 with its default setting and connecting it to a microcontroller. I send data on TXD line of st7540 at 2400 baud rate but i am unable to detect carrier frequency at TX_out line,
I have connected UART/SPI to 1 and RxTx to 0, already followed the datasheet to setup and spent so much time trying many different connections.
Does anyone know how to make this chip work??
Any help would be greatly appreciated!

 

magvi

Member

• Jul 21, 2012

• #2

try changing the baud rate . refer to page 16 and 17 of the datasheet
https://www.electro-tech-online.com/custompdfs/2012/07/CD00096923.pdf

 

ronsimpson

Well-Known Member

Most Helpful Member

• Jul 21, 2012

• #3

Have you read this?

 

H

hayowazzup

New Member

• Jul 21, 2012

• #4

I have read the datasheet and the application note and tried all possible wiring connection. I have also tried setting the chip to read and write the control register but the chip did not make any response at all. Referring to the application note page 14, there's a resistor R20 at the output of TX_Out, is that the same as the resistor R3 in the schematic diagram on Page 40 of the datasheet?

 

Last edited: Jul 21, 2012

ronsimpson

Well-Known Member

Most Helpful Member

• Jul 22, 2012

• #5

UART/SPI pin is high/low???
Is the oscillator working? What frequency?
REG_DATA pin is high/low???

 

H

hayowazzup

New Member

• Jul 22, 2012

• #6

UART/SPI pin is high, actually I tried both high and low.
Is the oscillator working? What frequency? Yes it is working at 16Mhz
REG_DATA pin is low (tried both, in the datasheet it says the content of the control register can be read at RxD after setting REG_DATA to high and RxTx to high, but it didn't work for my chip)

 

H

hayowazzup

New Member

• Jul 22, 2012

• #7

Does the Watchdog reset matter? I am keeping it at low

 

ccurtis

Well-Known Member

• Jul 22, 2012

• #8

I have also tried setting the chip to read and write the control register but the chip did not make any response at all.

Click to expand...

Per datasheet, control register is not accessible in Uart mode. It can be accessed in SPI mode only but in that case did you try to communicate with the chip with an SPI interface?

Maybe you can help me with a question. The control register is crucial to the operation of the chip, but it is inaccessible if the HOST has only a Uart interface with the chip. What good is the Uart interface if an SPI interface is necessary anyway, via which all functions can be performed? I must be missing something.

 

Last edited: Jul 22, 2012

H

hayowazzup

New Member

• Jul 22, 2012

• #9

Yes, I did tried to read the register in SPI mode, sorry about that I didn't make it clear.
I guess Uart interface can be used sometimes if the Host's SPI interface is being used by other perpherial, but the host won't able to access the control register.

 

Last edited: Jul 22, 2012

ccurtis

Well-Known Member

• Jul 23, 2012

• #10

I guess Uart interface can be used sometimes if the Host's SPI interface is being used by other perpherial, but the host won't able to access the control register.

Click to expand...

Thanks. That makes sense. Though I don't have specific help for you, I think you are on the right track to concentrate on figuring out a basic write/read of the control register as a first step. Stuff on the mains side of the chip should not affect that ability, unless it is damaging it.