need switchable spi... 74ls126 ok?

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#1
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I need to talk to 2 chains of spi devices... a bunch of spi leds and a bunch of 595s used as 'chip selects' for the leds... originally the pc guy had the spi talking to both at the same time.... but you cant disable the clk and data on either device, so when I talk to one, it messes up the other. So I'm thinking just hang a 74ls126 buffer on the clk and another one on the data to each device and enable clk and data to a set of devices one at a time. This sound ok to you hw guys? (I'm really more sw....) The cpu on the bd is a mega128 (need to talk about avrs!) Thanks!

Imagecraft compiler user

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hello bob,
use a cs for each spi chain and everything is fine.

regards
gerhard

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Hi,

I use a 74HC4053 on my board you can download the layout from my website www.ulrichradig.de (*.brd and *.sch)

Ulrich Radig

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You need a separate chip select for each device in the SPI system.

You can use any pin for the chip select as it is NOT auto-managed by the SPI master; it has to be managed by explicit software.

Jim

 

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