TXU0304: TXU0304

Manmohan garg

Part Number: TXU0304
Other Parts Discussed in Thread: SN74LVC125A, SN74LVC244A

Hi,

I need to use SPI master/slave configuration, have one STM32 as master uC as SPI master & 6 STM32 are slaves, i was trying on one prototype which involved external wiring, bus without repeater, facing issues in SPI communication, it can work for lower frequency less than 400kHZ, then i thought to use bus repeater, if I use TXU0304 for all 4 signals(MISO/MOSI/CS/CLK),which way is correct, one TXU0304 is for one slave(means total 6 TXU0304- input is common & output is dedicated to each slave) or I can use only one TXU0304 for all 6 slaves, Please advice which is the best methodology.

Thankyou.

Manmohan

over 1 year ago

0 Clemens Ladisch over 1 year ago

Guru 318660 points

If the voltages are the same, then you can use plain buffers (e.g., SN74LVC125A, SN74LVC244A).

How many buffers to use depends on the length of the wiring they need to drive. When in doubt, use separate ones.

Please note that the MISO lines can be connected together only if you ensure that inactive slaves do not drive it. This is normal for actual SPI devices, but it is likely that you must connect the respective /CS to /OE for the buffers.

0 Manmohan garg over 1 year ago in reply to Clemens Ladisch

Prodigy 20 points

Thanks Clemens!!

SPI bus length is more than 50cm, Going to use same voltage on both sides, I want to use this for communication on high speed, without any buffer i am facing issues on clk frequency more than 500Khz. not sure whether plain buffer will be ok for Hi-speed like 10Mhz or more.

i have one application in which 6 slaves,in other application 12 slaves are there, definitely I am going to use one slave at a time using CS/OE control.

0 Clemens Ladisch over 1 year ago in reply to Manmohan garg

Guru 318660 points

Check the voltages with an oscilloscope. If there are reflections at the edges, add proper termination (the easiest is source termination, i.e., a resistor of about 22 Ω … 33 Ω at the driver). If the clock line picks up noise, you would need shielding, or you would have to use a differential protocol like LVDS.

0 Manmohan garg over 1 year ago in reply to Clemens Ladisch

Prodigy 20 points

Thanks Clemens!! I think now I got it.

Logic

Logic forum

TXU0304: TXU0304