Driving the PMOD SSD from Xilinx SDK

[fpga_123]

Hello,

 

I have a block design to drive the SSD using the AXI GPIO IP as illustrated in the figure. The SSD external interface is 8 bits(7 data bits + 1 select_segment bit).  In SDK, I can write a C code to display the number from 0x0 to 0xF on one segment, however, I am not sure how to display number on both the segments at the same time from the SDK. I do have an idea that for using both the digits, we need to alternate between the two digits faster than our eye can perceive, say in terms of milli seconds. But how to achieve that in SDK? Also, is it possible to work on the logic of scrolling the digits on the two segments form left to right or vice versa?

 

Thanks,

[Niță Eduard]

Hello,
Your idea is indeed correct, alternating between the displays really fast gives the illusion that both are turned on at the same time.
As of implementing it, you could do something similar to this pseudocode

selection <- read selection bit

while(program runs){
data0 <- aquire digit value for display 0
data1 <- aquire digit value for display 1
display0 <- translateData(data0) // translate data0 into a seven segment encoding
display1 <- translateData(data1) // translate data1 into a seven segment encoding
if(selection == 0) then
	write display0 to data bits of the SSD
else
	write display1 to data bits of the SSD

selection <- negated(selection) 
}

Best wishes,
Eduard