7 ms·

>some models simply won't run if the infotainment system is broken; the navigation GPS provides the vehicle's master time counter, and without that, the powertr

>some models simply won't run if the infotainment system is broken; the navigation GPS provides the vehicle's master time counter, and without that, the powertrain won't function :O

kortex 7y ago
This is purely sloppy. Dealt with a similar issue on a UAV project. We elected to check for a gps time (which fails if, e.g. indoors), and fall back to os system time, with a note in the logs. It can't do anything mission critical without gps anyway, so this only even shows up in dev/debug settings.
- masklinn 7y ago
  I'd guess they use GPS as ntp (rather than direct time source which as you note would dangerously fail in plenty of normal situations). But since the infotainment already dealt with time, they just used that as a "system clock" straight, so without infotainment there's no "system clock" to be had.
- dwyerm 7y ago
  Is your OS time at least battery backed? I can tell you that nightmares start when all your clocks go back to 1970 on boot, and you need a clock to validate certificates on boot...
mrtksn 7y ago
This sounds like a swoftware written by an oldschool electrical engineer or something. I mean, in electromechanical systems that do not have computers, engineers find interesting ways to do more advanced things. For example, ovens with clocks keep track of time through the grid frequency and if the grid frequency changes, the clocks diverge too.
- taneq 7y ago
  Any time you get cross-disciplinary stuff done by people significantly lacking in experience in one of the disciplines, you get stuff like this. Programmer art (shudder), artist code (double shudder), EE software, software engineer circuit board layout, mechanical engineer wiring... Smart people will figure something out but it always looks janky to specialists in the figured-out field.
  - pingyong 7y ago
    Even just between different SE fields this can happen to a degree. Let a C++ programmer write a website with PHP and Javascript - it will probably work, but I'd guess for a web dev the code would look a quite weird.
  - ivanhoe 7y ago
    And the same applies for people criticizing the fields they know little about. I'm pretty sure that not all electrical engineers in the world are idiots and that there's a solid reason why they've chosen the grid frequency as a standard way of doing it. One thing that comes to mind is that the crystal oscillators frequency is very temperature sensitive, so probably not ideal solution for using in ovens?
    - mrguyorama 7y ago
      It's because it saves several dollars on the BOM, and really an oven probably doesn't need a hyper accurate clock
      - opencl 7y ago
        Grid frequency actually is hyper accurate in a lot of places. i.e. in the Western US the grid is regulated such that a clock running off it will never deviate more than 2 seconds from the atomic clock derived National Bureau of Standards time [1]. Compare to a typical quartz oscillator which will gain or lose around 15 seconds per month. [1] https://www.naesb.org//pdf2/weq_bklet_011505_tec_mc.pdf https://www.naesb.org//pdf2/weq_bklet_011505_tec_mc.pdf
- ivanhoe 7y ago
  and famously if there's ever a blackout, most of modern ovens will refuse to work until you setup the clock... never seizes to piss me off each time I have to do it...
  - lini 7y ago
    This is a security feature. Most modern ovens allow you to set a timer with auto shut-off. This is very useful if you want to go out and come back to a ready meal. You can imagine what would happen if the power went out for a while and after it came back the oven switched on automatically. Refusing to turn on the oven when the clock is not set is the easiest way to prevent problems when it is in use.
    - ivanhoe 7y ago
      good point... still, quite annoying when you come to check your meal cooking in the oven for the last hour, only to find out that it never actually switched on because of the clock :)
dognotdog 7y ago
Balkanization is about right. In my experience developing driver assistance systems, there are enormous efforts spent on political turf wars instead of proper design and engineering. This is not surprising, as the team structures, at least as of a few years ago, were traditionally set up with tradtional manufactirng in mind, around parts and control modules, while the functionality exploded (within 1 or 2 generation of cars) and crossed those boundaries without adequate processes in place properly architect the interactions from a bird's-eye view, creating major computing power, network bandwidth, and most importantly to OEMs, cost bottlenecks. And as cost is king, nobody wants to budge on increasing cost on their own module, and critical architectural decisions aren't made as much as put off until there isn't any other choice left except to hacking in the most critical bits with one eye closed and hoping somebody else's jenga tower falls first. That, I imagine, is how you get that GPS time thing, I can see how it all started: "Oh, I can save $.30 on my module if I don't put in an RTC, that'll get me a nice bonus for cost saving, GPS is going to have one anyway ..."
- castratikron 7y ago
  I've worked in that environment before. It doesn't help when upper management has no software or hardware background whatsoever (e.g. MBA or "sales" or whatever) and in that case the only way they see things is in terms of dollars. One time I was working on a new project and I wanted to put an SD card on the board so that we could have a log. I was asked how much the log was "worth" so that they could justify the cost of the extra hardware.
  - cameronbrown 7y ago
    > One time I was working on a new project and I wanted to put an SD card on the board so that we could have a log. I was asked how much the log was "worth" so that they could justify the cost of the extra hardware. Very much like testing. Incalculable if you need it (and you certainly do), but managers who don't understand, just assume that you're doing something wrong if you need to "waste time" reading logs or writing tests rather than adding features.
  - TwoBit 7y ago
mandeepj 7y ago
And, they like to call themselves as "Tesla Killers" :-)

>some models simply won't run if the infotainment system is broken; the navigation GPS provides the vehicle's master time counter, and without that, the powertrain won't function :O

kortex 7y ago

This is purely sloppy. Dealt with a similar issue on a UAV project. We elected to check for a gps time (which fails if, e.g. indoors), and fall back to os system time, with a note in the logs. It can't do anything mission critical without gps anyway, so this only even shows up in dev/debug settings.

masklinn 7y ago
I'd guess they use GPS as ntp (rather than direct time source which as you note would dangerously fail in plenty of normal situations). But since the infotainment already dealt with time, they just used that as a "system clock" straight, so without infotainment there's no "system clock" to be had.
dwyerm 7y ago
Is your OS time at least battery backed? I can tell you that nightmares start when all your clocks go back to 1970 on boot, and you need a clock to validate certificates on boot...

mrtksn 7y ago

This sounds like a swoftware written by an oldschool electrical engineer or something. I mean, in electromechanical systems that do not have computers, engineers find interesting ways to do more advanced things. For example, ovens with clocks keep track of time through the grid frequency and if the grid frequency changes, the clocks diverge too.

taneq 7y ago
Any time you get cross-disciplinary stuff done by people significantly lacking in experience in one of the disciplines, you get stuff like this. Programmer art (shudder), artist code (double shudder), EE software, software engineer circuit board layout, mechanical engineer wiring... Smart people will figure something out but it always looks janky to specialists in the figured-out field.
- pingyong 7y ago
  Even just between different SE fields this can happen to a degree. Let a C++ programmer write a website with PHP and Javascript - it will probably work, but I'd guess for a web dev the code would look a quite weird.
- ivanhoe 7y ago
  And the same applies for people criticizing the fields they know little about. I'm pretty sure that not all electrical engineers in the world are idiots and that there's a solid reason why they've chosen the grid frequency as a standard way of doing it. One thing that comes to mind is that the crystal oscillators frequency is very temperature sensitive, so probably not ideal solution for using in ovens?
  - mrguyorama 7y ago
    It's because it saves several dollars on the BOM, and really an oven probably doesn't need a hyper accurate clock
    - opencl 7y ago
      Grid frequency actually is hyper accurate in a lot of places. i.e. in the Western US the grid is regulated such that a clock running off it will never deviate more than 2 seconds from the atomic clock derived National Bureau of Standards time [1]. Compare to a typical quartz oscillator which will gain or lose around 15 seconds per month. [1] https://www.naesb.org//pdf2/weq_bklet_011505_tec_mc.pdf https://www.naesb.org//pdf2/weq_bklet_011505_tec_mc.pdf
ivanhoe 7y ago
and famously if there's ever a blackout, most of modern ovens will refuse to work until you setup the clock... never seizes to piss me off each time I have to do it...
- lini 7y ago
  This is a security feature. Most modern ovens allow you to set a timer with auto shut-off. This is very useful if you want to go out and come back to a ready meal. You can imagine what would happen if the power went out for a while and after it came back the oven switched on automatically. Refusing to turn on the oven when the clock is not set is the easiest way to prevent problems when it is in use.
  - ivanhoe 7y ago
    good point... still, quite annoying when you come to check your meal cooking in the oven for the last hour, only to find out that it never actually switched on because of the clock :)

dognotdog 7y ago

Balkanization is about right. In my experience developing driver assistance systems, there are enormous efforts spent on political turf wars instead of proper design and engineering. This is not surprising, as the team structures, at least as of a few years ago, were traditionally set up with tradtional manufactirng in mind, around parts and control modules, while the functionality exploded (within 1 or 2 generation of cars) and crossed those boundaries without adequate processes in place properly architect the interactions from a bird's-eye view, creating major computing power, network bandwidth, and most importantly to OEMs, cost bottlenecks. And as cost is king, nobody wants to budge on increasing cost on their own module, and critical architectural decisions aren't made as much as put off until there isn't any other choice left except to hacking in the most critical bits with one eye closed and hoping somebody else's jenga tower falls first. That, I imagine, is how you get that GPS time thing, I can see how it all started: "Oh, I can save $.30 on my module if I don't put in an RTC, that'll get me a nice bonus for cost saving, GPS is going to have one anyway ..."

castratikron 7y ago
I've worked in that environment before. It doesn't help when upper management has no software or hardware background whatsoever (e.g. MBA or "sales" or whatever) and in that case the only way they see things is in terms of dollars. One time I was working on a new project and I wanted to put an SD card on the board so that we could have a log. I was asked how much the log was "worth" so that they could justify the cost of the extra hardware.
- cameronbrown 7y ago
  > One time I was working on a new project and I wanted to put an SD card on the board so that we could have a log. I was asked how much the log was "worth" so that they could justify the cost of the extra hardware. Very much like testing. Incalculable if you need it (and you certainly do), but managers who don't understand, just assume that you're doing something wrong if you need to "waste time" reading logs or writing tests rather than adding features.
- TwoBit 7y ago

mandeepj 7y ago

And, they like to call themselves as "Tesla Killers" :-)