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  1. I just measured my shifters again but this time...

    I just measured my shifters again but this time using my dso quad's PWM output at 2mhz and I get about ~15ns knee to knee -- will do the exact same test with the txs0108e-q1 when it arrives and see...
  2. That said, I noticed that my measured, *actual*...

    That said, I noticed that my measured, *actual* interrupt latency is currently ~25ns, measuring from the trigger level of the input going low (so 0.3*vdd) to the knee of the output data (so as soon...
  3. Okay, I'm not trying to be rude but I'm not sure...

    Okay, I'm not trying to be rude but I'm not sure of your ability to help if you're unable to get it working off what I've posted - I appreciate you are trying to help, and great if you can.

    But...
  4. I did post the entire program minus the...

    I did post the entire program minus the proprietary data in binaryBytes which can simply be FF's for testing.

    Not sure about any double lines except things that might be commented which if...
  5. I'll take a look, thanks.. "zero" though? there...

    I'll take a look, thanks.. "zero" though? there was an application note for 1050 on measuring interrupt latency and their example only got down to like 75ns, doing it I think the same way I am, which...
  6. thanks binaryBytes is just the data to be...

    thanks



    binaryBytes is just the data to be outputted on the data pins. Can be whatever you want for testing. It'll be an array of 32768 bytes (65536 if using all 16 address lines for 512k/64kb...
  7. hm...so what could be causing the sketch every I...

    hm...so what could be causing the sketch every I see every ~50 sec? Nothing in my code that I can tell...



    Adding it seemed to change nothing in any behaviour, I was considering using...
  8. So I got curious and put my scope on the input...

    So I got curious and put my scope on the input and output of my level shifters.. I didn't think they'd be causing any delay, but it seems like there's a bit.

    From the knee of the output driving...
  9. I know it can be triggered manually, like I could...

    I know it can be triggered manually, like I could trigger it from my ISR.. and perhaps it might be faster to move data.. what I was wondering was if it could somehow be triggered automatically...
  10. Doesn't millis wrap at 47 sec or so? Which would...

    Doesn't millis wrap at 47 sec or so? Which would explain my 'about 50s' glitch..
  11. Sure, it's worth a shot I just should know how it...

    Sure, it's worth a shot I just should know how it works and if/what else it could break. Will have to check the code..

    Do you know if there's any way to trigger DMA directly somehow? Id love if I...
  12. Disabling interrupts was simply a test hoping...

    Disabling interrupts was simply a test hoping that the ~50 sec and usb jitter might be solved by not having my interrupt interrupted..but had no effect.

    Again (replying in reverse order) the...
  13. I haven't fully wrapped my head around the yield...

    I haven't fully wrapped my head around the yield thing, what does it typically do/why/link to good doc?
  14. The loop code doesn't affect the ISR even by a...

    The loop code doesn't affect the ISR even by a single ns, it's incomplete, the actual code has a delay to slow down the output but even without it has no effect. I left the code in to sort of show...
  15. T4.1 Interrupts, DMA, USB, nanosecond timing

    Hi,

    As some of you may know, I've been experimenting with making an (E)EPROM emulator with a T4.1. This is essentially implemented as a parallel I/O, 15-16 address lines from the host, 8 datalines...
  16. I2C has two addressing modes, 7 and 10 bit but I...

    I2C has two addressing modes, 7 and 10 bit but I think after that, due reserved bytes etc, transfers can be arbitrary.

    Technically, a serial bus is a 1-bit bus anyway - just depends how you frame...
  17. Yes, I understand that. You'll still need to...

    Yes, I understand that. You'll still need to likely send data to the device, writing to registers to set options and such, to configure the device appropriately before you can start reading it from...
  18. You mention it's Arduino compatible, and it seems...

    You mention it's Arduino compatible, and it seems like your eval board is a shield... I'd be willing to bet there's already a library out there for you to more easily use this device in that case, it...
  19. So, you are going to send an SPI transfer with...

    So, you are going to send an SPI transfer with the address of the register you want to read from or write to. I think if writing you can send with that transfer. Then the AD7768 should send a...
  20. I'd have to look at the datasheet and have a...

    I'd have to look at the datasheet and have a think .. I'm more familiar with i2c, usually try to use that instead of SPI if I can, and even then often I've used libraries.

    I'd guess if...
  21. Hi, I'll try my best to help if I can. I...

    Hi,

    I'll try my best to help if I can.

    I think in this situation, SPI is SPI - the amount of data the device puts out is unrelated. Although, you'll have to make multiple transfers to get a...
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    Definitely seems like USB serial might be...

    Definitely seems like USB serial might be affecting it somehow.. I can push data out quite quickly over serial6 over an ftdi and receive it without any hiccups in the ISR.. only when I use...
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    So my next problem.. doing anything else.... heh...

    So my next problem.. doing anything else.... heh

    Interrupts are set to highest priority.

    Trying to even just print CPU temperature over serial, once per second, maybe once every 10 seconds or...
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    Is it just me or shouldn't the slew rate seem a...

    Is it just me or shouldn't the slew rate seem a bit tighter?

    25096

    25ns/div .. taking like 25ns to change states..? Slope gets slightly steeper without a load on the pin but not much..? I can...
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    register uint32_t address = GPIO6_PSR >> 16; ...

    register uint32_t address = GPIO6_PSR >> 16;
    GPIO7_DR = ((binaryBytes[address] + (binaryBytes[address] << 12)) & OUTPUT_MASK);


    vs.



    GPIO7_DR = ((binaryBytes[GPIO6_PSR >> 16] +...
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    FASTRUN didn't seem to make a difference. :(

    FASTRUN didn't seem to make a difference. :(
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    I know the feeling, I've put other stuff behind...

    I know the feeling, I've put other stuff behind this week because I've been obsessing over this. Truth be told, I've wanted to build an emulator for a very long time.

    You should definitely be...
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    Thanks, I admit my c/c++ is a little rusty -- I...

    Thanks, I admit my c/c++ is a little rusty -- I thought GPIO6_PSR was just a macro to the memory address, not a defined variable..?



    Hm, you make a point (again rusty).. For GPIO2_ISR, I could...
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    I saw FASTRUN somewhere before but couldn't get...

    I saw FASTRUN somewhere before but couldn't get it to work in my brief testing - but I think I did it wrong (the definition link in my IDE didn't immediately pop up, leading me to think it was...
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    Thanks, I'll definitely take this into account. ...

    Thanks, I'll definitely take this into account.

    I assumed with reading GPIO6_PSR twice within a single operation that the compiler would just optimize that out - but I haven't checked any assembly...
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    Teensy can emulate an eprom at ~80ns so far....

    Teensy can emulate an eprom at ~80ns so far. Working in my target and my chip reader.

    Thanks to everyones help.. woot
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    Fastest so far (from INPUT pin triggered low to...

    Fastest so far (from INPUT pin triggered low to data outputting as shown on scope) is about 75ns with static data and 100ns with actual data (at 900mhz).. the app note for ISR latency and your...
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    It seems to read the addresses just fine. Never...

    It seems to read the addresses just fine. Never had an issue with reading addresses just everything else, haha..but I see that note and maybe PSR is better - maybe this explains some interesting...
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    I've tried this: unsigned SPEED_MASK ...

    I've tried this:



    unsigned SPEED_MASK = 0b0000'0000'0000'0000'0000'0000'1100'0001;
    ..
    IOMUXC_SW_PAD_CTL_PAD_GPIO_AD_B1_00 |= SPEED_MASK;
    IOMUXC_SW_PAD_CTL_PAD_GPIO_AD_B1_01 |=...
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    Thanks..good to know..ill make note of that.. ...

    Thanks..good to know..ill make note of that..

    don't know wtf happened to the usb..nothing shorted or anything.. just tried the higher clock and when it didn't respond, tried to reprogram it and...
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    Killed my teensy?

    edit: teensy is fine. panicked early. :)

    Was trying to see if overclocking would help my timings at all..

    set_arm_clock(720000000); at first then
    set_arm_clock(800000000); then
    ...
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    So, on the scope I'm showing about 160ns between...

    So, on the scope I'm showing about 160ns between OE# going low and data going high with static data, closer to 180ns when using real data.

    Also,



    if (digitalReadFast(35) == HIGH) {

    ...
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    I DID IT!#@% I've read back a whole 32k chip with...

    I DID IT!#@% I've read back a whole 32k chip with the willem eprom reader. No errors, perfect readback.

    Now, will it be fast enough for the ECU and can I share address lines with the ecu..will...
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    For your curiosity and my sanity I just wired up...

    For your curiosity and my sanity I just wired up the extra 8 data pins and will try and feed my Willem..give me a few
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    So, if I take an address pin that's having...

    So, if I take an address pin that's having issues, say A12 and put it just to my scope to watch the high/low..

    Then I trigger OE# low, which sets GDIR to output..

    Then I pull all address pins...
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    Typically, you'd expect this. On older devices...

    Typically, you'd expect this.

    On older devices (such as my target device), to save pin counts, the lower address lines are shared with the data lines. The address is pushed into a latch, latched...
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    Okay, so.. I swear these types of issues only hit...

    Okay, so.. I swear these types of issues only hit me..? I hope not..

    So, something I edited out of the above post because I figured it out, bit #30 was 'sticking' .. reseated my eeprom and seems...
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    GPIO_GDIR issue

    Thought I'd make a new thread since this is sort of a separate issue and since my original thread my project might not even be using DMA, heh..

    edit: I maybe figured out the GPIO_GDIR part, I...
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    For sure, especially if I get help getting it...

    For sure, especially if I get help getting it going, lol. This GDIR issue makes zero sense to me. Unless something is changing in the mux when I change it, which I'm not touching any mux...
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    reading the manual I wondered if it was: ...

    reading the manual I wondered if it was:


    GPIO_EDGE_SEL may be used to override the ICR registers' configuration. If the
    GPIO_EDGE_SEL bit is set, then a rising edge or falling edge in the...
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    seems like pull ups are still enabled when I set...

    seems like pull ups are still enabled when I set input too..can't have that lol
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    looking at digital.c in pinMode, void...

    looking at digital.c

    in pinMode,



    void pinMode(uint8_t pin, uint8_t mode)
    {
    const struct digital_pin_bitband_and_config_table_struct *p;
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    we all want jtag! everywhere! lol

    we all want jtag! everywhere! lol
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    Hmm..doesn't seem to like me.. If I set a pin...

    Hmm..doesn't seem to like me..

    If I set a pin change ISR and use it to update an address variable which my main loop occasionally prints, I can see the addresses count up as expected.

    If I use...
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    So, ...

    So,


    attachInterrupt(digitalPinToInterrupt(37), pinChangeISR, CHANGE);

    seems to work reliably, what sort of magic is this..? I supppose I should be diving into the teensy lib source stuff..
    ...
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