I've found a few minor design issues which I don't think will affect us in the short run, but may not be what we want:
1) I already told you (Bob) about the addresses for the Max temp sensors. As set, they collide with two of the possible 4 addresses on an ADS7828, a commonly-used and space-tested A/D converter that some satellite might use. We talked about this before and it should all be straightened out.
2) I just noticed that PWR_SW_AX5043 and PWR_SW_SSPA are connected to AD1IN_8 and AD1IN_5, pins 78 and 83. They are used as input to the MAX4995SAL power switch/limiter. While you could use these AD1IN pins as an input GPIO (read the voltage and subject it to a threshold for high or low), I don't think it is possible to use these for output. AD1EVT might be usable for output but I'm not sure what effect it would have on the bult-in a/d converter. I suppose you could use the nearby MIBSPI5 pins. They appear to be usable as GPIO pins and are physically near the ADC pins.
I think the current way it is will work for the moment, since if I read the datasheet right, the "ON" pin or the MAX4995AL really should be ON_N. That is, a low value on it turns the power on, and you have a pulldown there. So I think the 5043 and the SSPA will always be on since the ADC inputs should be high impedance.
3) This may just be a doc issue. I think that "PWR_FLAG" on the schematic can't be a circuit, right? OTherwise you'd have lots of weird stuff connected together. If they are actually test points, I think they should be labelled as such (TP1, TP2, etc) and marked in silk screen on the board.
4) And finally, from what I have read (and seen on other projects), I don't think the SPI busses need pullup resistors EXCEPT for MISO, and that one should be VERY weak. (One of our devices does not use MISO very often but it appears not to be able to pull much current, thus requiring the really weak pullup. But as I recall a builtin pullup either was not enough, or it could not be used when the pin was used as an SPI device). I can put a scope on the MISO line for the AX5043 to see if it is getting pulled down enough with the 10K. Likewise, I'll see what the other pins look like when connected to the push/pull output of the SPI master.
Don't take these critiques as anything other than helpful. I'm no expert here...I just found these things in the process of trying to debug the software, and in a couple cases from tracking down some really PITA problems on Fox and/or Golf!
73,
Burns Fisher, WB1FJ *AMSAT(R) Engineering -- Flight Software*