oresat / oresat-proto-card Goto Github PK

Prototype card for the OreSat bus. Requires the OreSat Backplane.

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oresat-proto-card's Introduction

"oresat-proto-card"

This is the "prototype" card for OreSat, meant to pioneer future cards and test the backplane, and be an easy way to hack in functionality. NOT MEANT FOR FLIGHT.

Features

Populates the two 1.27 mm connectors from the backplane.
Populates all three SMPM RF connectors from the backplane.
Standard TPS63070-bsaed buck/boost SPS (Vin = 2.5 to 7 V, Vout = 3.3V)
Has our standard/favorite STM32F042K6 microcontroller.
- With SWD, UART (FTDI), and CAN (to the backplane).
Has lots of breakouts, but DO NOT POPULATE THE 0.1 IN CONNECTORS, THEY'RE TOO TALL!!!

Connector information

Main 1.27 mm connector ("Center" connector)
- Samtec TFM-120-01-L-D-RA
- https://www.digikey.com/products/en?lang=en&site=US&keywords=TFM-120-01-L-D-RA
- Drawing: http://suddendocs.samtec.com/prints/tfm-1xx-xx-xxx-d-xxx-mkt.pdf
- Brochure: http://suddendocs.samtec.com/catalog_english/tfm.pdf
- 3D CAD: https://www.samtec.com/partnumber/tfm-120-01-l-d-ra?vendor=digikey#technical
- Notes: the -RE1 model is better because of the solder stakes, but the female connector doesn't fit! The stakes get in the way :(
Auxiliary 1.27 mm ("alt-left" connector)
- Samtec TFM-110-01-L-D-RA
RF (70 cm, L band, S band) conenctors
- Card
  - Molex 73300-0030 (possible replacement is 73300-0020 but it has full detent that we don't want)
  - SMPM Connector Plug, Male Pin 50 Ohm Board Edge, Cutout; Surface Mount Solder, smooth bore
  - Molex w/3D: https://www.molex.com/molex/products/datasheet.jsp?part=active/0733000030_RF_COAX_CONNECTORS.xml
- Barrell (connects card to backplane)
  - Molex 73300-0220 (alt but slightly different lengths: -0223, -0228)
  - SMPM female to female barrel adapter
  - RF Adapters - In Series SMPM JACK/JACK BULLET .21IN
  - Molex w/3D: https://www.molex.com/molex/products/datasheet.jsp?part=active/0733000220_RF_COAX_CONNECTORS.xml

OreSat Power Domain (OPD)

You can find more design information on the OPD here.

LICENSE

This documentation describes Open Hardware and is licensed under the CERN OHL v. 1.2.

You may redistribute and modify this documentation under the terms of the CERN OHL v.1.2. http://ohwr.org/cernohl. This documentation is distributed WITHOUT ANY EXPRESS OR IMPLIED WARRANTY, INCLUDING OF MERCHANTABILITY, SATISFACTORY QUALITY AND FITNESS FOR A PARTICULAR PURPOSE. Please see the CERN OHL v.1.2 for applicable conditions.

Version Information

Version	Date	Notes
3.0	2018/11/22	Big changes in structure, mostly springs. Changed RF connectors to SMPM. Optimized layout for more proto area.
2.0	2018/03/??	New 1.27 mm connectors, again.
1.0	??	New connectors.

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oresat-proto-card's Issues

Add FFC to protocard BOM

BOM: R64 (0.1 ohm shunt) not in BOM?

Fix TNAME placement of U12

Add bypass caps to the OPD MIC842s

BOM: C18 and C15 should be 0603, not 0402

I2C protection

Weird gate capacitance stuff happens with the I2C protection circuit. New design coming in future revs to fix issue. For now DNP the I2C MOSFETS and short the lines together.

OPD breaker trips with inrush current.

the OPD breaker trips from the inrush current when the board is powered on. Can be reset, stuffing the reset circuitry should fix the problem

Getting feedback on the v1.1 prototype card

Rough draft of the v2 card is done! We're now awaiting feedback that we're not complete idiots on the v1.1. We need to know:

Does it power up?
Can you program the STM?
Can you blink the LED?
Can you talk over UART?
Can you talk over CAN?

At that point, we can fire on v2!

Update documentation to reference the f09

Some pieces of documentation still reference the f04

R50 and R51 should be 4.7k (fix in design block too)

FTDI Header has TX/RX swapped

USART2_RX should connect to pin 4 (RXI)
USART2_TX should connect to pin 5 (TXO).

IO0 on MAX7310 is open drain

IO0 on the IO expander is only open drain, needs to be switched with one of the other pins that can work with open drain (I2C?). Cutting the trace and soldering a jumper from tp13 to tp10 to tie to the indicator LED should work as a temp fix.

Power LED labelled VBAT instead of VBUS

Simple as that. The LED for power is labelled VBAT and I noticed everything else is labelled VBUS now.

Implement inhibit RC filter on MAX4311 CB IC

See design.md in the protocard repo: C = 1 uF (Vw >= 16V), R = 100k, and then a 10k into the MAX4311 to protect it.

Protocard: Ciss (input capacitance) from P CH in OPD protection circuitry kills I2C rise times

The 300 pF input capacitance of the DMP2240UDM-7 dual P channel MOSFET (Q10) we use in the I2C protection circuit (before the MAX7310) was killing the I2C signal. Removing the MIC comparitor, and just having the 10K to ground on the Q10 gates was too much. Raising that resistor to > 100k seems to solve the problem "enough".

So: change R77 and R81 to 665K (we already have that value) and move them between the MIC output and transistor. We'll have to no longer have the gate be pulled low, which seems OK? If we really want one, a 1 M to ground is probably OK but it'll affect the gate drive of the MIC so that'll have to be explored.

Oh hey, our latest design has Vpv and Vbatt being the same bus. Doh!
Better SWD connector footprint, it should show the polarization key.
Ask K about what he wants: easy ground clip points, easier access to power, etc.
Come up with a standardized card-edge debug connector that has power, SWD, UART, CAN, Etc.