SDI Video crosspoint Switch

[Vishug]

Hi, everyone
I am designing a 4x4 video switch using the ic MAX4359/MAX4456. I am having trouble in setting up the control lines for the ic has anyone worked wit these ic?

 

[danadak]

Setting up how, in software, hardware, describe a little more in-depth
the problem and symptoms you are seeing ....maybe post a schematic....


Regards, Dana.

 

[Vishug]

Setting up as in controlling the ic functionality with the given control pins. i have attached the shematic of my design i have used bnc connectors of 75 ohms for sdi input and output with MAX4359 for switching and max4395 as the output driver. Right now i have given berge stick headers for the control pins and using a STM32L1 discovery board for controlling these pins.

as the controls pins are simple digital pins so i am thing the issue is with the timing of the LAT and WR pin
as for the other pins they are in the following configuration
SER/~PAR~ = LOW
Load = HIGH
CE = HIGH
Edge/~level~= LOW

Regards,
vishu

 

[rjenkinsgb]

The device appears to be SPI compatible, with data to D0 and clock to WR, with the data load on the positive edge or WR.

You need to send four bits per device output, so 16 bits for the four output device.

Pulse LAT low after transferring all data, to load the control registers from the SPI input shift register.

The only restrictions I can see are minimum times for date setup and hold, and the delay from the final WR before the /LAT pulse.

The maximum SPI speed looks to be around 3MHz and with minimum 80nS delay from last WR to /LAT. Slower clock and longer delays are fine.

(The clock rate could be higher with different data/clock timing, but for simple SPI with the clock edge in the middle of the data, 3MHz is a safe limit).