Led Dot Matrix Display

[NewBee_SAfrica]

Hi All,
I am tring to build a dotrix display comprising (7 x 5) times 8. this goives 40 columns. I would like to use a microcontroller and vertically strobe the display. I was thinking of using cascaded 4017's or 74ls164 shift registers.  The shift registers would have a 1 cycled through them while the 4017's would sequence themselves.
Which would be the better option?

[justDIY]

i didn't read the datasheet a thousand times yet, but it doesn't look like the 164 allows "daisy chaining" of the chips, instead relying on a chip-select / reset line ... the disadvantage here is you either need a discrete output on your uC for each chip select line, or yet another chip to toggle the chip select lines.

my recommendation is the 74HC595 ... it's a serial in parallel out shifter like the 164, but it also supports daisy chaining, so you can treat it as a nBit register instead of just 8bit like the 164, for example four 595's "in series" gives you a single 32 64 bit register

for strobing the rows of the array, you can either use discrete pins off the uC to toggle power transistors (row drivers), or use a single pin off the uC as a clock for a 4017, and use it to toggle the row drivers.

for more gorey details see my blog articles on the subject of LED matrices here and here

ps, i've moved your thread to our microcontroller section

[NewBee_SAfrica]

thanks Justdiy,

Will have a look at the 74HC595