https://uwmidsun.atlassian.net/browse/MH-152
J1772 Interface
- When board is powered, Regulator U3 should output 5V otherwise the PP and CP readings may be off.
- Y1 should output a 16MHz wave otherwise CAN may not work as expected.
In case documentation and instructions here are not clear enough, see this link: https://blog.digital-scurf.org/posts/evse-tester-prototype/ (unfinished but better than most stuff on the internet)
Proximity Pilot (PP)
“Parallel resistance” refers to the resistors on pin 5 on the connector side.
Expected readings:
EVSE_PROXIMITY Parallel Resistance (Ohms) | U4 Inverting Input Voltage (V) | PA7 Voltage (V) |
|---|---|---|
Not Connected (infinite) | 4.46 | 2.735 |
480 | 2.77 | 1.938 |
150 | 1.53 | 0.938 |
- PA7 should always be DC. Time constant for RC filter (R8, C10) = 10us = 100kHz
- PA7 should never exceed 3.3V
Control Pilot (CP)
Status | EVSE_CONTROL_PILOT Voltage (V) | PA6_AN6_CONTROL_PILOT_PWM Voltage (V) | PA5_AN5_CONTROL_PILOT_SENSE Voltage (V) |
|---|---|---|---|
A (standby) | 0 | 0 | 0 |
B (vehicle detected) | +9/-12V square wave 1kHz | +2.87/0V square wave 1kHz | 2.87 * duty cycle |
C (ready) PA2_CONTROL_PILOT_SELECT must be ON to enter this state | +6/-12V square wave 1kHz | +1.27/0V square wave 1kHz | 1.27 * duty cycle |
- PA5 should always be DC. Time constant for RC filter (C17, R20) t = 0.1s = 10Hz
- Neither PA6 or PA5 should exceed 3.3V
- Duty cycle depends on maximum current allowed for charging
Relay Controls
- Both PB7 and PB9 should be enabled before any power is detected on 12V_CONTACTOR_COIL_SW (cathode of D9).
- When both are enabled, 12V_CONTACTOR_COIL_SW should be at 12V.
- When both are enabled, initial current should be approx 30A and LED3 should turn on. It should be enough to close the relay.
- The relay should open if PB7 or PB9 (or both) are off.