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anvyl:refmanual [2014/09/11 21:48] – [Table] Joshua Woldstadanvyl:refmanual [2016/04/11 16:33] (current) – Martha
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   * GPIO: 14 LEDs (10 red, 2 yellow, 2 green), 8 slide switches, 8 DIP switches in 2 groups and 4 push buttons   * GPIO: 14 LEDs (10 red, 2 yellow, 2 green), 8 slide switches, 8 DIP switches in 2 groups and 4 push buttons
   * breadboard with 10 Digital I/O’s    * breadboard with 10 Digital I/O’s 
-  * 32 I/O’s routed to 40-pin expansion connector (I/O’s are shared with Pmod connectors) +  * 32 I/O’s routed to 40-pin expansion connector (I/O’s are shared with Pmod ports) 
-  * seven 12-pin Pmod connectors with 56 I/O’s total+  * seven 12-pin Pmod ports with 56 I/O’s total
   * ships with a 20W power supply and USB cable   * ships with a 20W power supply and USB cable
  
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 |                        |      |                          |     |                        |     | LD13:          | W4   |                      |       | |                        |      |                          |     |                        |     | LD13:          | W4   |                      |       |
 |                        |      |                          |     |                        |     | LD14:          | U8   |                      |       | |                        |      |                          |     |                        |     | LD14:          | U8   |                      |       |
 +
 +
 +----
 +
 +====== Seven Segment Displays ======
 +
 +The Anvyl board contains three 2-digit common cathode seven-segment LED displays. Each of the two digits is composed of seven segments arranged in a “figure eight” pattern, with an LED embedded in each segment. Segment LEDs can be individually illuminated, so any one of 128 patterns can be displayed on a digit by illuminating certain LED segments and leaving the others dark. Of these 128 possible patterns, the ten corresponding to the decimal digits are the most useful.
 +
 +The common cathode signals are available as six “digit enable” input signals to the three 2-digit displays. The anodes of similar segments on all six digits are connected into seven circuit nodes labeled AA through AG (so, for example, the six “D” anodes from the six digits are grouped together into a single circuit node called “AD”). These seven anode signals are available as inputs to the 2-digit displays. This signal connection scheme creates a multiplexed display, where the anode signals are common to all digits but they can only illuminate the segments of the digit whose corresponding cathode signal is asserted.
 +
 +A scanning display controller circuit can be used to show a two-digit number on each display. This circuit drives the cathode signals and corresponding anode patterns of each digit in a repeating, continuous succession, at an update rate that is faster than the human eye response. Each digit is illuminated just one-sixth of the time, but because the eye cannot perceive the darkening of a digit before it is illuminated again, the digit appears continuously illuminated. If the update (or “refresh”) rate is slowed to a given point (around 45 hertz), then most people will begin to see the display flicker.
 +
 +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.
 +
 +{{ :anvyl:sev1.png?500 |}}
 +
 +//Fig. 14. Seven-segment displays.//
 +
 +{{ :anvyl:sev2.png?300 |}}
 +
 +====== Expansion Connectors ======
 +
 +The Anvyl board has a 2x20 pin connector and seven 12-pin Pmod ports. Pmod ports 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 port 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 ports. We have a set of recommended Pmods for the Anvyl called the “Anvyl Pmod Pack”.
 +
 +{{ :anvyl:exp1.png?400 |}}
 +
 +The 40-pin expansion connector has 32 I/O signals that are shared with Pmods JD, JE, JF and JG. It also provides GND, VCC3V3, and VCC5V0 connections.
 +
 +| //**Pmod JA**//         || //**Pmod JB**//         || //**Pmod JC**//         || //**Pmod JD**//         || //**Pmod JE**//        || //**Pmod JF**//        || //**Pmod JG**//        ||
 +| JA1:             | AA18  | JB1:             | Y16   | JC1:             | Y10   | JD1:             | AB13  | JE1:             | U10  | JF1:             | V7   | JG1:             | V20  |
 +| JA2:             | AA16  | JB2:             | AB14  | JC2:             | AB12  | JD2:             | Y12   | JE2:             | V9   | JF2:             | W6   | JG2:             | T18  |
 +| JA3:             | Y15   | JB3:             | Y14   | JC3:             | AB11  | JD3:             | T11   | JE3:             | Y8   | JF3:             | Y7   | JG3:             | D17  |
 +| JA4:             | V15   | JB4:             | U14   | JC4:             | AB10  | JD4:             | W10   | JE4:             | AA8  | JF4:             | AA6  | JG4:             | B18  |
 +| JA7:             | AB18  | JB7:             | AA14  | JC7:             | AA12  | JD7:             | W12   | JE7:             | U9   | JF7:             | W8   | JG7:             | T17  |
 +| JA8:             | AB16  | JB8:             | W14   | JC8:             | Y11   | JD8:             | R11   | JE8:             | W9   | JF8:             | Y6   | JG8:             | A17  |
 +| JA9:             | AB15  | JB9:             | T14   | JC9:             | AA10  | JD9:             | V11   | JE9:             | Y9   | JF9:             | AB7  | JG9:             | C16  |
 +| JA10:            | W15   | JB10:            | W11   | JC10:            | Y13   | JD10:            | T10   | JE10:            | AB8  | JF10:            | AB6  | JG10:            | A18  |
 +
 +//Table 2. Pmod pinout.//
 +