Why not just use a ripple latch for each column and send the data "serially" ? The data is sent as a continuous stream, and a clock shifts the bits in and out, and each bit comes out when an "update command" is issued I can not remember the chip # but it is a common 74 or 40 serries latch with serial in and parallel out. Regards, Kat. ----- Original Message ----- From: "rad0" To: Sent: Monday, August 20, 2001 12:32 AM Subject: Re: [EE]: LED Matrix : there's got to be a cheaper way? > > How about a couple latch chips (a column select latch and row latch) and a > > for each character and updating to the next column on every sweep? You'll > > probably want transistors to better drive them. Even a 0.7" LED matrix > taht > > I am using is almost begging for transistors, right now it is directly > > driven by an 'F872, I am not using multiple displays. > > > > There are tricks to save here and there but a large set of LED matrices is > > going to cost you. > > > > Jeff > > Thanks > > how would I catch the serial bytes that I am sending out to each matrix? > > is there such a thing as a latch that has a serial input? > > > with a pic, I want to use 3 lines to each matrix, ground, pwr, and serial... > > and these could be common to all...each matrix listening for it's address > and > ignoring everybody else... > > -- > http://www.piclist.com hint: To leave the PICList > mailto:piclist-unsubscribe-request@mitvma.mit.edu > > -- http://www.piclist.com hint: To leave the PICList mailto:piclist-unsubscribe-request@mitvma.mit.edu