- Muchas notas - Fran Acién

20230210 - TFM - First meeting with Denis

The SSCB:

  • It has a fpga
  • there is a debugger interface. SWD programmer
  • 2 pins, subsystem select to multplex the signal.
  • The multiplex where wrong
  • I need to check the interface of the SSCB, Denis doesnt know exactly the interface with the programmer.
  • Maybe, hub with 4 ports to program, and then another as a dubugger.
  • Benjamin was the last student working on the SSCB. I received a mail with known boards.
  • The USB type c is connected to a breackout board, with a programmer and a small microcontroller with the system selection
  • In the Lora subsystem, it was developed with arduino but then Denis changed to LPC. MCU Xpresso to program it, there are some supported libraries for the interfaces of the microcontroller.
  • Denis was the cosupervisor of the project. It is basically a beagle bone, a bb image should powered on, it is necessary to change the device tree.
  • The usb and the OBC, should mount a network interface on USB, and I should be able to connect via ssh. Denis recomends me to take a breakout board and connect power suppies, SWD programmer and start from that.
  • The breakout board that I have has a problem and it is easy to confuse with the direction. A new breakout board, smarter, was developed but denis dont remember where.
  • PI network with Saturn PCB Design. Then put a comment “Zdiff=100 Ohm on this traces”. There is another software to get the values of the pi filters, SimSmith.
  • PCBExpert software to generate footprints.
  • I put a transceiver:
    • Get the input impedance of the transceiver from the datasheet. In the frequency of operation.
    • If the pin is 50 ohms and the connector is 50 ohms, check in jlcpcb how to get 50 ohms and put in the comments that you want 50 ohms.
    • If the connector is 100 ohm, put a pi filter, get the values with the software simsmith, and then ask jlcpcb to adjust the 50 ohms at the trace after the filter.

The interface of 40 pins:

  • The TBD are used in the OBC.
  • The SR are used on a shift register, that controls the power of the different subsystems.
  • MALE and FEMALE, convencion, female connector gives power, that is the decision.

Prototol in te communications:

  • A lot of discussion on the topic: Gomspace (SCP) made a protocol, also CCSDS was used. Denis used scp in the packet. SCP defines a framework between subsystems, there is no master. They did a project with GOMspace, and the communication was with SCP. The should be happy to help.

  • The resistors are to configure the board, the resistors should be desoldered.

  • 4 Latchup op amps.

  • FTDI, there is a UART interface. Probably not used as a programmer.

  • FX23 connector to stack more boards. DF17

  • LPCLink debugger at CIF, René remember a wrong version of the board in the CIF.