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- The Controls Leaderboard takes in a 12V line from the supplemental battery (through POW_2ND_CONN). This is a small 12V battery meant mainly for the startup of our boards; once the big battery pack is up and running, all low voltage power will switch to that.
- Note that there are 12 positions on the ignition switch, but corresponding pairs are connected as the ignition switch is rotated (1 and 7 are connected at the same time, 2 and 8 as well, 3 and 9, etc.)
- Diagonally opposite positions of our ignition switch are connected up at the same time. Note that it's essentially the same as two separate switches being "synced up", and this model is AKA a double pole switch.
- The bottom half of the ignition switch (pins 1 through 6) facilitates the LV on/off signal. Depending on the position of the Ignition Switch, this 12V will be routed to BPS_PWR_OUT. This connector is wired to the Power Board (formerly known as the Secondary Power Board). The idea is that we send 12V across this line once the ignition switch is turned to the appropriate position to signal that we would like power to be provided to our Low Voltage (LV) systems.
- As you can see in the diagram, BPS_PWR_OUT receives 12V at any position other than position 6 (same as position 12). This is because that is our off position, and in any other position we need the car to receive LV power.
- The top half of the ignition switch (pins 7 through 12) provides a digital signal to two pins on the Controls leaderboard (IGN1 and IGN2). As you can see in the diagram, each position labeled.
- Pos. 12 is OFF, and this corresponds with pos. 6 (since both connect to nothing)
- Pos. 11 is LV. This is allocated a position so that it only turns on LV and nothing else. In actuality, all the other positions will also turn on LV as well, but they will turn on other things too.
- Pos. 10 is ARR_ON. This is hooked up to the IGN_1 pin on the Controls Leaderboard in order to tell Controls to begin the Array Precharge sequence.
- Pos. 9 is MOT_ON. This is hooked up to the IGN_2 pin on the Controls Leaderboard in order to tell Controls to begin the Motor Precharge sequence.
- Any further positions (pos. 8 and 7) are also hooked up to IGN_2.
- Note that the intent of the Ignition Switch control is to make the positions cumulative. For example, when clicking from LV → ARR_ON, the low voltage systems will continue to remain active in the ARR_ON position. Furthermore, when clicking from ARR_ON → MOT_ON, both the array and the low voltage systems will continue to remain active in the MOT_ON position
Notes on Photocouplers and Voltage Domains
The 12V line on pins 7-12 is on the 12V power domain and is either cut off from ground or connected to GNDPWR, which is the 12V ground. This line goes through a rotary switch which determines whether current goes through the photocouplers or not.
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