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→Implementation
== Implementation ==
== Implementation ==
Below is a short guide/list of steps to guide the design and implementation of a board for the HONEY architecture. One should follow it carefully, as it is specifically written to prevent one from making mistakes by forgetting to implement a required functionality, or using a restricted functionality.
Below is a short guide/list of steps to guide the design and implementation of a board for the HONEY architecture. One should follow it carefully, as it is specifically written to prevent one from making mistakes by forgetting to implement a required functionality, or using a restricted functionality.
=== Required Implementation ===
1) Use the latest HABEES_STACK_TEMPLATE part from the Altium library. This is to be kept updated by HABEES members to reflect changes in pinout, physical layout, etc, and is required to make your board meet the physical and electrical bare requirements.
2) Common Ground all GND nets on the stack connectors to your GND -- this includes two on the Power Bus, four on the Data Bus, and one on the CAN bus.
3) For the nets of the power bus that your board is utilizing, make sure to electrically short the nets together, and join them by a 40/50-mil trace. The reason there are two pins is to provide a higher current-limit, so you should tie them together to ensure proper rating.
4) Make sure to '''NOT IMPLEMENT''' any of the following restricted pins, unless specifically agreed upon in advance (don't touch them at all, even as an input) -- 6 (R_MCU), 22 (RX2) 112 (CAN_MODE -- this shouldn't go anywhere except your Transceiver)
5) Make '''SURE TO IMPLEMENT''' the following pins as INPUTS to your MCU -- 7 (R_ALL), 8 (S_READY), 9 (LOW_PWR), 10 (FMODE), 11-14 (System Flags 3-6, reserved), 21 (CHIRP -- should go to a Serial RX pin on your MCU).
6) Make sure to properly implement the CAN Bus -- duplicate the existing schematic for the primary circuit, and verify that you have properly implemented the terminating impedance sub-circuit.
7) Be sure to connect pin 112 (CAN_SPD) from the data bus to the speed pin on your CAN Transceiver. Without this, it will not function.
8) Be sure to use +3.3_CAN pin from the CAN Bus EXCLUSIVELY to power your Transceiver, and make sure it powers nothing else.
9) Make sure pin 7 (R_ALL) is directly wired to your MCU reset pin, to allow Core Avionics remote reset.
10) If using RTC, make sure to implement pin 5 (+VBCKP).
11) Make sure no component of the board extends more than 0.25" over the board edge.
=== Self-Help FAQ ===
1) If implementing the data bus SPI or I2C lines, this should be agreed upon by current HABEES members as an appropriate use of the Core Avionics I2C/SPI buses before action is taken.
2) If using either of the dedicated Core Avionics Hardware UARTs (pins 23/24 and 25/26), this should be agreed as constituting a reasonable use -- being that it is critical enough to warrant their use, or otherwise cannot be achieved.
3) If using either DAC (pins 27 and 28) verify it can only be used as an input, and will not be used in any way as an output (IE do not output to those pins).
4) If using any of the Core Avionics GPIO's on the data bus (pins 29-36, 38-41), be sure that it isn't currently being used by another board (unless you specifically want it to be, such as using the pin as a feed-through signal line), whether the pin is able to perform the desired action (PWM, ADC, DIO), and agree amongst HABEES members that it is a reasonable and just usage of the pin, which would henceforth be reserved for your purpose.
5) If using any of the current RESERVED pins (37, 42-111, 113-120), agree amongst HABEES members that it is a just and fair usage of the pin, which would henceforth be reserved for your purpose.
6) Make sure, unless for some reason you're using it, CAN2 is not connected to anything.
7) Make sure +3.3_CAN is used only to power the transceiver, and nothing else.
8) Make sure CAN_SPD is hard-wired to the transceiver speed pin.