Application Board Development
This reference document explains how to create a custom application specific circuit board for interfacing to the AMMDK-CCB. It is intended to be similar to a Raspberry Pi hat, or an Arduino shield.
There are five main constraints when designing an AMMDK application board: the physical circuit board dimensions, the locations of the mounting holes, the locations of the three mating connectors, the data signals provided, and the power rails provided.
The dimensions of the circuit board are specified in the "application_board_outline" DXF and PDF files. This is the largest area circuit board which will fit entirely within the bounds of the AMMDK main board, while avoiding large connectors and the CPU heatsink. An application board designer may extend beyond the bounds of the main board if desired. When placing components on the underside of an application board, care must be taken to avoid components on the main board.
The three mounting holes are 3.2 mm diameter, and must accommodate an M3 screw with a 6 mm diameter head. Their locations are specified in the "application_board_outline" DXF and PDF files. The spacing between the AMMDK main board and application board is 8 mm, or approximately 5/16". The following components are known good matches for mounting the two boards together:
| Component | Manufacturer | Part Number |
|---|---|---|
| Board Support Snap Lock | Essentra Components | DLMSPM-5-01 |
| Board Support Snap Fit | Essentra Components | MSPM-5-01 |
| Unthreaded Spacer | Essentra Components | 13SP045 |
The simplest way to begin designing an application board is to use the provided Altium Designer CAD files. Either the existing generic application board or the blank application board may be used. They may be edited and expanded upon, leaving the power and GPIO connectors, and mounting holes in place.
If Altium Designer is not used, DXF and PDF files of the PCB outline, mounting hole locations, and connector locations have been provided.
The AMMDK main board supplies 3.3 V, 5 V, and 12 V power rails at 5 A each to the application board. A complete list of power rails and GPIO signals available to AMMDK application boards is available here. If other signals, buses, protocols, or voltages are desired, they will need to be generated on the application board.
Application boards interface to the AMMDK main board through three electrical connectors: one power, and two GPIO data. They are:
| Component | Manufacturer | Part Number | Quantity |
|---|---|---|---|
| 16 pin power connector | Hirose Electric Co Ltd. | DF11-16DP-2DSA(01) | 1 |
| 40 pin GPIO connector | Harwin Inc. | M55-7004042R | 2 |
The connectors are keyed, therefore orientation is critical. See the reference image below.
