OPD (OreSat Power Domain)

The OPD allows the C3 to turn other cards on or off, with the exception of the solar cards. The solar cards are directly power off the output their solar panels and not the batteries. Yes, the battery cards are also on the OPD, as the batteries will work regardless of the whether the card is enable or not. Enabling the battery card(s), allows for telemetry from the battery card; i.e.; voltage level, charge level, etc.

How It Works

Every card, other the solar cards, has a MAX7310 to control giving power to the card. The MAX7310 is 8-pin GPIO expander with an I2C interface.

_images/opd.jpg

3 of the 8 pins are standardized on all cards to be for Not Fault, Enable, and CB Reset.

  • Not Fault Pin: Is a input pin. When it is High, the circuit is does not have a fault; when it is low the circuit has a fault.

  • Enable Pin: Is an output pin. When set High, the card is enabled (powered on). When the pin is set Low, the card is disable (powered off).

  • CB Reset Pin: The circuit breaker reset is an output pin. It can reset the enable circuit. When held high for a little while, it will hopefully clear the fault.

Note

Any pin that is not used is consider a test point and is set low.

OPD on STM32 Cards

On top of the standard 3 pins, the STM32-based cards also utilizes pins for an I2C bootloader and enabling a UART connection.

  • I2C SCL Pin: Is an input pin. Used by I2C bootloader.

  • I2C SDA Pin: Is an input pin. Used by I2C bootloader.

  • Boot Pin: Is an output pin. When set high before being the Enable pin is set, will put the STM32 into bootloader mode.

  • UART ENABLE Pin: Is a output pin. When set high, the cards will be connected to the C3’s UART bus.

OPD on Ocatvo A8 Cards

On top of the standard 3 pins, the STM32-based cards also utilizes pins for boot selection pin and enabling a UART connection.

  • Boot Pin: Is an output pin. When set high, the card will boot off of the eMMC; when set low, the card will boot off of the SD card.

  • UART ENABLE Pin: Is a output pin. When set high, the cards will be connected to the C3’s UART bus. This will allow the cards eMMC to be reflashed.

OPD State Machine

class oresat_c3.subsystems.opd.OpdState(value)[source]

OPD subsystem states.

DISABLED = 0

OPD subsystem is off.

ENABLED = 1

OPD subsystem is on (no faults).

FAULT = 2

OPD subsystem is on and has one or more faults.

DEAD = 3

OPD subsystem is consider dead (too many faults in a row).

stateDiagram-v2 [*] --> DISABLED DISABLED --> ENABLED: Subsystem is enabled ENABLED --> DISABLED: Subsystem is disabled ENABLED --> FAULT: Subsystem has a fault FAULT --> ENABLED: Subsystem was reset and then fault cleared FAULT --> DISABLED: Subsystem is disabled FAULT --> DEAD: Subsystem failed to reset multiple time in a row

OPD Node State Machine

class oresat_c3.subsystems.opd.OpdNodeState(value)[source]

OPD node states

DISABLED = 0

OPD Node is off

ENABLED = 1

OPD Node is on

FAULT = 2

Fault input is set for OPD node

DEAD = 3

OPD node is consider dead (too many faults in a row).

NOT_FOUND = 255

OPD node is not found

stateDiagram-v2 [*] --> DISABLED: Node is found [*] --> NOT_FOUND: Node is not found NOT_FOUND --> DISABLED: Node is found DISABLED --> ENABLED: Node is enabled DISABLED --> NOT_FOUND: Node is lost ENABLED --> FAULT: Node has a fault ENABLED --> NOT_FOUND: Node is lost ENABLED --> DISABLED: Node is disabled FAULT --> ENABLED: Node was reset and then fault cleared FAULT --> NOT_FOUND: Node is lost FAULT --> DISABLED: Node is disabled FAULT --> DEAD: Node failed to reset multiple time in a row