Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

Multiplexing two SPI Master

Status
Not open for further replies.

wat007

Junior Member level 3
Joined
Apr 28, 2009
Messages
27
Helped
2
Reputation
4
Reaction score
2
Trophy points
1,283
Activity points
1,455
Is it possible to switch two master SPI lines using Quad 2:1 multiplexer like (74HC257)? I want my two Master devices to access a single SPI slave (Flash). SPI speed is 4MHz. Please see attached schematics.

The reason for this is that, I have an MP3 module (master2) which already has a flash that I want my MCU (master1) to access the data from. I don't have control on SPI lines of MP3 (Master2). Schematics.jpg
 

KlausST

Super Moderator
Staff member
Joined
Apr 17, 2014
Messages
19,727
Helped
4,344
Reputation
8,697
Reaction score
4,304
Trophy points
1,393
Activity points
130,568
Hi,

Your multiplexing should work.

MISO doesn't need to be switched.
I'd add a pullup resistor at !CS of flash.

You need an arbitration before switching MUX to prevent data corruption.

Klaus
 

wat007

Junior Member level 3
Joined
Apr 28, 2009
Messages
27
Helped
2
Reputation
4
Reaction score
2
Trophy points
1,283
Activity points
1,455
Thanks KlausST, I will post my results soon.
 

Status
Not open for further replies.

Similar threads

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Top