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SN74LV8153-Q1: data transmision protocol

Oscar Conteras
Prodigy 10 points
Part Number: SN74LV8153-Q1
Other Parts Discussed in Thread: SN74LV8153

Did I get it rigth??

 

from the data sheet:

"The serial data should be sent as 2START-3ADDRESS-4DATA-1STOP. Two consecutive serial-data frames transmit 8 bits of data. The first frame includes the lower four bits of data (D0-D3), and the second frame includes the upper four bits (D4-D7).

The order of the two start bits must be 0, then 1 in any frame;..."

This SN74LV8153-Q1 serial to paralel converter is compatible with UART serial data format. The UART data frame is :  1start BIt -- 8 data bits -- parity bit -- stop bit.

the UART trasmiter will add the start, stop and parity bit, then, I have 8 data bits I can manipulate to make the (2START-3ADDRESS-4DATA-1STOP).

The start bit in UART protocol is always logic 0.

then I will set my first data bit to logic 1 to comply with the two startbits SN74LV8153-Q1 data format

then the 2rd, 3th anf 4th bits are the adrress 

then the last 4 bits will be the data

data frame: blue set by UART transmiter, green data set in the UART transmiter by user.

 

Start Bit always 0 // firts data bit set to 1 //  address 3 bits // data 4 bits// stop

UART timing diagram.svg

So from the 8 bits of UART data frame, I have to set

bit 0 = 1  second start bit of SN74LV8153-Q

bit 1,2,3 = address

bit 4,5,6,7 = data

  • 0
    TI__Guru* 96591 points

    Hi Oscar and welcome to the forums!

    Directly below the quote you provided from the datasheet, there's a diagram showing exactly what each bit should be:

    So, sending 1 byte of data requires 2 bytes of input, with the first containing D[0:3] and the second containing D[4:7] -- both must be addressed to the appropriate SN74LV8153.

    *****

    It sounds like your question is primarily about UART and if you can get UART to build the bytes for you.  I'm afraid I can't answer that -- you'd have to check into how your controller communicates over UART. Are you using a TI microcontroller?