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also I sanity checked the logic analyzer a bit with an analog scope and the debug port signals are beautifully clean and all of this test equipment is calibrated
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Mar 18, 2015 05:51
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I am going to feel like the most colossal idiot when I figure this out.
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Mar 18, 2015 05:52
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cadence, do a thing, please
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Mar 18, 2015 05:52
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Bloody posted:the baffling output is a completely invalid control character that the block's spitting out pretty reliably. is the bit wrong or the character is the bit calculated in any way separately from the rest does the byte predictably match any nearby byte in the stream
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Mar 18, 2015 06:35
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it isnt happening this morning 
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Mar 18, 2015 16:53
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but you stored the old traces right? don't worry, it'll reproduce when you pull the shades up in the afternoon
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Mar 18, 2015 16:56
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Bloody posted:i have a lookup table mapping 10-bit values to 9-bit values. every possible 10 bit input is accounted for. you would think that, given absolutely arbitrary 10-bit input, it would be utterly impossible to get a 9-bit output that does not exist in the table. it depends on what the function that maps 0-1024 to 0-512 is if you're just chopping off a bit, sure you should have each 9-bit value in that table twice if you're doing something else, there's a good chance it'll miss some 9-bit values
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Mar 18, 2015 17:02
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he mentioned it, it's 8b/10b like in older gen PCIe. the 10b encodings are chosen to maintain DC balance on the line, the 9th bit is really just "it's not data, it's a COM/STP/SDP byte or other framing info" so there are a lot of values from 256-512 that you wouldn't ever expect to see
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Mar 18, 2015 17:05
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Bloody posted:it isnt happening this morning you need to perform an exorcism on the FPGA, sorry
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Mar 18, 2015 19:47
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everything works, hail satan
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Mar 18, 2015 23:04
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Bloody posted:it isnt happening this morning lol timing
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Mar 19, 2015 07:13
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i've just finished getting our custom jtag subsystem working (since we love doing things the hard way), because we want to be able program/debug msp430s and various other poo poo in-system -- so much hdl, now i can move on to real work like all the hardware that's like a month behind schedule incidentally the ft2232h is a pretty neat chip -- anyone using the bus blaster w/ adaptive clocking and urjtag?
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Mar 19, 2015 07:14
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movax posted:i've just finished getting our custom jtag subsystem working 
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Mar 19, 2015 07:31
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movax posted:urjtag?
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Mar 19, 2015 13:40
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So the power supply I got has three hot rails and three ground rails. The thing I'm plugging it into is expecting only one +24V. Along with switching the polarity of the two bottom leads, is it possible to do something to remove or do something with the other two +24V leads without modifying the thing I'm plugging it into? OEM power supply:  Power supply I bought: 
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Mar 25, 2015 15:22
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the NC pins probably aren't connected to anything so you probably should be ok probably clip the wires if you want to be certain.
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Mar 25, 2015 15:28
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hobbesmaster posted:the NC pins probably aren't connected to anything so you probably should be ok So I guess just clip them and wrap with electrical tape? Should that be enough insulation? I'm just paranoid of something arcing or short circuiting and causing a fire lol.
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Mar 25, 2015 15:52
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tape will be fine, 24V isn't going to arc
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Mar 25, 2015 15:58
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Chill Callahan posted:So I guess just clip them and wrap with electrical tape? Should that be enough insulation? I'm just paranoid of something arcing or short circuiting and causing a fire lol. you're not going to arc something and cause a fire with a 24V DC power supply. well, unless there is something fundamentally wrong with the wall side of the power supply
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Mar 25, 2015 16:11
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Cool thanks!!!! 
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Mar 25, 2015 16:29
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imagine, if you will, that this is Sochi and we have two toilets in the same room. and there's a bunch of people in the room who communicate by flushing these two toilets in various prescribed patterns and watching the water levels. iiuc this is basically how i2c works
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Mar 25, 2015 17:23
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Mr Dog posted:imagine, if you will, that this is Sochi and we have two toilets in the same room. and there's a bunch of people in the room who communicate by flushing these two toilets in various prescribed patterns and watching the water levels. "Oh, my husband used all the hot water. This means I need to buy eggs"
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Mar 25, 2015 17:37
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Mr Dog posted:imagine, if you will, that this is Sochi and we have two toilets in the same room. and there's a bunch of people in the room who communicate by flushing these two toilets in various prescribed patterns and watching the water levels. now imagine using it for input devices one of which is a mouse that's round and uses two little wheels that don't work instead of a roller ball or optical sensor
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Mar 26, 2015 05:23
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eschaton posted:
i used to use those, i liked them a bunch
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Mar 26, 2015 14:56
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how is arduino forking or panelizing or however you call it when it's open hardware going
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Mar 31, 2015 08:04
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Bloody posted:as a general idea yes but all extant implementations no computers in a nutshell
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Mar 31, 2015 20:14
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Mr Dog posted:imagine, if you will, that this is Sochi and we have two toilets in the same room. and there's a bunch of people in the room who communicate by flushing these two toilets in various prescribed patterns and watching the water levels. wasn't this basically how the first practical telegraphs worked? a guy in Paris pushing a lever on a hydraulic pipe that signified a letter?
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Mar 31, 2015 20:31
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Luigi Thirty posted:wasn't this basically how the first practical telegraphs worked? a guy in Paris pushing a lever on a hydraulic pipe that signified a letter? semaphore relay towers, which makes perfect sense but i never would have thought of. they're referenced in a subplot of the count of monte cristo.
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Apr 2, 2015 14:17
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eschaton posted:now imagine using it for input devices wait are people complaining about i2c? it's a pretty easy bus to use, not sure how you would get in to trouble unless you were using really wonky pull up or termination values. Although I guess sometimes it's hard to see which device is loving up the bus, which is why a little series termination on your bus can be nice because the voltage will be a little higher/lower on one side of the series terminator depending on which side is pulling down
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Apr 2, 2015 22:58
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i2c is great but i'll never understand why every device datasheet has timing diagrams explaining the protocol like give me a register map and call it a day, there's no need to put the exact same timing diagrams on every single datasheet
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Apr 2, 2015 23:11
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yeah seriously what's up with that but i mean, they usually explain SPI too, and there's really not that much to explain there.
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Apr 2, 2015 23:32
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JawnV6 posted:i2c is great but i'll never understand why every device datasheet has timing diagrams explaining the protocol some of us go *just* long enough between i2c implementations to forget. Also every so often a device fucks around with the usual setup and doesn't have sub addresses or does some other weird thing start - address w - sub address - start - address r - sweet data - stop managed to forget the sub address the first time so I guess I'm the guy those are for also IMO all i2c addresses should have the msb set to protect us from the 50/50 split of people who do/don't include the r/w bit in the address when writing it in hex
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Apr 2, 2015 23:33
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you shouldn't be bit banging it anyway "hey HW module on this mcu, talk to address X, write data Z to register Y then read register Q" if you can't tell if it's a 7/8 bit address by looking at it idgaf
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Apr 2, 2015 23:52
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Mr Dog posted:yeah seriously what's up with that explaining spi is nice because it's so loosely defined. the poo poo i have seen, man. i have seen some poo poo. lvds spi. ddr spi. spi where chip select actually does nothing and god help you if you have anything but the most pristine clock line from power up until forever. gently caress spi. i2c is nice if you don't mind some slow as rear end upper limit and don't have to talk to it with an fpga
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Apr 3, 2015 00:48
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Bloody posted:lvds spi that smiley with the eyeballs
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Apr 3, 2015 00:52
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Apr 3, 2015 01:28
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at what point do you just call it an arbitrary serial protocol. it's SPI if my mcu's hardware serial thingy can talk to it in SPI mode. lvds ddr "SPI" is just trolling
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Apr 3, 2015 02:08
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Bloody posted:explaining spi is nice because it's so loosely defined. the poo poo i have seen, man. i have seen some poo poo. lvds spi. ddr spi. spi where chip select actually does nothing and god help you if you have anything but the most pristine clock line from power up until forever. i2c ultra fast mode can do 5Mb/s, oooh yeaaaaaah, i did pre-silicon verification of the i2c and displayport aux channel controller in bay trail and i used to have dreams about i2c i spent so much time fiddling with it in the day for a few weeks there
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Apr 3, 2015 02:19
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spi is "anything with at least one shift register that connects to the outside world and maybe a select line", yes
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Apr 3, 2015 14:56
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movax posted:i've just finished getting our custom jtag subsystem working (since we love doing things the hard way) 
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Apr 3, 2015 15:05
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