Expansion connectors – Digilent 410-258P-KIT User Manual
Page 15
Anvyl Reference Manual
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In order for each of the six digits to appear bright and continuously illuminated, each digit should be
driven once every 1 to 16ms (for a refresh frequency of 1KHz to 60Hz). For example, in a 60Hz
refresh scheme, the entire display would be refreshed once every 16ms, and each digit would be
illuminated for 1/6 of the refresh cycle, or 2.67ms. The controller must assure that the correct anode
pattern is present when the corresponding cathode signal is driven. To illustrate the process, if Cat1 is
asserted while AB and AC are asserted, then a “1” will be displayed in digit position 1. Then, if Cat2 is
asserted while AA, AB and AC are asserted, then a “7” will be displayed in digit position 2. If Cat1 and
AB, AC are driven for 8ms, and then Cat2 and AA, AB, AC are driven for 8ms in an endless
succession, the display will show “17”. An example timing diagram for a two-digit controller is shown
below.
An un-illuminated seven-segment display, and nine
illumination patterns corresponding to decimal digits
A
F
E
D
C
G
Individual anodes
Common cathode
Two-digit Seven
Segment Display
B
Fig. 14. Seven-segment displays.
Expansion Connectors
The Anvyl board has a 2x20 pin connector and seven 12-pin Pmod connectors. Pmod connectors are
2x6 right-angle, 100-mil female connectors that work with standard 2x6 pin headers available from a
variety of catalog distributors. Each 12-pin Pmod connector provides two 3.3V VCC signals (pins 6
and 12), two Ground signals (pins 5 and 11), and eight logic signals. VCC and Ground pins can
deliver up to 1A of current. Pmod data signals are not matched pairs, and they are routed using best-
available tracks without impedance control or delay matching. Digilent produces a large collection of
Pmod accessory boards that can attach to the Pmod connectors. We have a set of recommended
Pmods for the Anvyl called the “Anvyl Pmod Pack”.