max7221 cascade mode

if i connect two max7221 in cascade mode(dout of the first on din of the second)how i can switch between the two?

lutherblissett, What you would do is commect them in series as you have but then use a seprate I/O line for each going ti the chip select line. The shift register is pass thru so you would just send the first 16 followed by the second 16 bits then strobe the chip select lines on each of the devices. The data is only read form the registers of each of the 7221's when the chip select line is toggled.

Dave Purola,
N8NTA