Using LEDs

For some labs this term, you must use the LEDs on the boards as output. Thus, as an aid to learning how to assign to and use LEDs, here is a quick reference:

Bit Assignments

The numbers above correspond to bit values used to assign to the LEDs. For example, displaying a '4' would require setting bits 5, 4, 3, and 1 to '1' and the others to '0'. The resulting std_logic_vector would be '0111010'.

Pin Assignments

	XS40			XSA
Segment	XStend Left LED (active-low)	XStend Right LED (active-low)	Upper LED (active-high)	XStend Left LED (active-low)	XStend Right LED (active-low)	Upper LED (active-high)
0	p3	p59	p25	p64	p47	p67
1	p4	p57	p26	p65	p40	p39
2	p5	p51	p24	p66	p28	p62
3	p78	p56	p20	p50	p29	p60
4	p79	p50	p23	p51	p27	p46
5	p82	p58	p18	p54	p42	p57
6	p83	p60	p19	p56	p48	p49

ASCII Reference:

(Lab 4)

Display characters: Some imagination may be required for the K, M, V, W, and X, since it is rather difficult to make all 26 letters display distinctly and recognizably in a single digit LED without diagonals. However, this is typical for logic design, where creativity and compromise are constantly required. Note that the ASCII line shows the what character the LED is trying to resemble, but all the codes (input to the display unit) on the HEX line are for the UPPERCASE letters, which is what the display unit expects. Unknown codes (such as lower case letters) result in no LED output

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Using LEDs

Bit Assignments

Pin Assignments

ASCII Reference:

Created by Paras Mehta, 2003