#garfield Logs

Dec 08 2021

12:31 AM rue_mohr: something changed in gcc
12:39 AM rue_mohr: I'm having to add "extern" to things in header files
12:03 PM aandrew: rue_mohr: of course
12:39 PM polprog: ru
12:40 PM polprog: eh
12:40 PM polprog: rue_mohr: happy birthday!
01:26 PM Tom_L: hmm, it is?
04:52 PM aandrew: it's rue's birthday today?
04:52 PM aandrew: Happy Birthday, Rue!
04:52 PM polprog: computer says so
04:52 PM polprog: :P
05:06 PM polprog: WormFood??
05:07 PM WormFood: Yes?
05:07 PM WormFood: What's up?
05:08 PM polprog: Nothing. just a name i recognize.. i didnt see you here before
05:08 PM polprog: Nice to see you
05:08 PM WormFood: I've been here, semi-regularly, for the last 2 months or so I suppose
05:08 PM polprog: Cool
05:09 PM polprog: Are you still doing AVRs?
05:09 PM WormFood: Yes indeed I am.
05:10 PM polprog: I've been mostly doing stm32 recently
05:10 PM WormFood: I just updated my AVR "baud" rate calculator
05:10 PM polprog: Or older stuff
05:10 PM polprog: Oh nice. I used it a couple times
05:11 PM WormFood: and, I'm on an active project right now. The path to where I'm going leads through nrf24l01+ land, so I've been playing with that lately.
05:13 PM WormFood: in fact, I'm working on a test program, to learn more about dealing with these wireless modules. I think it may be very interesting for some of you guys working with this stuff.
05:13 PM polprog: I was caught up in uni stuff but I will be coming back to hardware hacking for my thesis hopefully
05:13 PM WormFood: That'd be cool
05:13 PM polprog: Gotta finish the board hacking guide too
05:14 PM polprog: https://polprog.net/rozne1/ircjunk/z80/boardhacking.txt
05:14 PM * WormFood looks
05:16 PM WormFood: The title is confusing.
05:17 PM polprog: Its WIP
05:17 PM polprog: i dont have a better idea
05:17 PM WormFood: Is it anything more than reverse engineering?
05:17 PM polprog: It's reverse engineering for a specific type of PCBs (that exposed EPROM)
05:18 PM polprog: So systems like 8051 or z80 based stuff
05:18 PM WormFood: so, if it has no eprom, or eeprom, then this guide isn't for you?
05:19 PM polprog: rue and me were running own code on random 8051 PCBs we found, i wanted to make a universal procedure for figuring out the memory map
05:19 PM polprog: pretty much
05:19 PM polprog: it's about figuring out memory maps mostly
05:20 PM WormFood: Exploring and mapping alien worlds through the memory interface.
05:20 PM rue_mohr: :) thanks
05:20 PM polprog: good title :)
05:22 PM WormFood: My first computer (that I owned) had an interesting hardware interface. There are addresses that change the machine's operation, just by reading from them. No need to write, only read.
05:22 PM polprog: Do you like it?
05:22 PM polprog: Yeah, i know about these
05:22 PM WormFood: Yeah. I think it has potential
05:22 PM polprog: As long as its not a killer poke its fine
05:22 PM polprog: Thanks!
05:22 PM WormFood: a killer peek
05:22 PM polprog: What was your first computer?
05:23 PM WormFood: The first computer I ever used, was a terminal on a mainframe, back in the late 79s
05:23 PM WormFood: 70s&
05:24 PM WormFood: But the first computer I owned was the highly underrated Tandy Color Computer, running the Motorola 6809 CPU, and packing 64k of ram.
05:24 PM polprog: Which mainframe?
05:24 PM WormFood: Later, I got a new model, of the same computer, and upgraded it to 512k of ram.
05:24 PM rue_mohr: I still want generic 8031 code that, with a single feedback line, works out the memory address of perphials for you
05:24 PM rue_mohr: prints them via serial
05:25 PM WormFood: I don't know what they were running. I was just a kid at the time. It was, I'm 99.999% sure, a unix machine. Probably a pdp11 or something. I imagine someone could find out, since it was at the University of North Florid (Jacksonville)
05:25 PM WormFood: I have something you might find interesting.
05:26 PM WormFood: A way to transmit data to a serial port, running at a different speed.
05:26 PM rue_mohr: 8031 makes it easy, built in serial ""
05:26 PM WormFood: AVR A running at 9600 baud, sending data to AVR B running at 4800 baud.
05:27 PM rue_mohr: "its serial captin, but not as we know it"
05:27 PM rue_mohr: I might pull of uc-less serial tonight
05:27 PM polprog: Many moons ago i was considering making a bus where you had two speed data transmission at different times. Something like baudrate domain multiple access
05:27 PM WormFood: The only problem is, you can't get the full character set. You're limited to what characters will work.
05:27 PM rue_mohr: turns out, connecting a 1.8432MHz crystal to a 4060 generates 115k baud in 7 bit count
05:28 PM polprog: Youd have devices which talked at say, 9600 and devices which talked at 115200
05:28 PM polprog: Your idea is also interesting
05:28 PM rue_mohr: I gnereated a rom image last night for a serial message
05:28 PM rue_mohr: need to burn and wire it
05:29 PM polprog: And in my case receiving a completely different baudrate frane would just cause a frame error (hopefully), so that you could selectively send data to fast and slow devices just by changing the baudrate. Of course its nonsense but its an unusual idea
05:30 PM rue_mohr: that BASIC has autobaud detector
05:30 PM rue_mohr: a lost art
05:30 PM polprog: Yeah
05:30 PM WormFood: If you configure your AVR that is running exactly 2X the speed of the other AVR, and configure it for 2 stop bits, no parity, and either 5, 7 or 9 data bits, then some patterns of bytes, will produce useful data on the slower receiver
05:31 PM polprog: yeah. Similar to serial port music
05:32 PM WormFood: my computer didn't have a parallel printer port...in fact, it didn't even have a uart (that was an option), and they made serial to parallel converters, and one day, they lost their bitrate knobs, and became auto detecting.
05:32 PM WormFood: I came to the conclusion, that it would be damn near impossible, to with a 100% accuracy rate, guarantee the source speed.
05:34 PM polprog: Yeah, however if you put a linecode on it, then you could avoid the problem caused by repeating symbols
05:34 PM polprog: like, bit stuffing
05:34 PM rue_mohr: the basic just requries you hit space first
05:34 PM polprog: but thats uart
05:34 PM rue_mohr: times the first bit
05:34 PM polprog: Yeah, that makes thing simpler
05:36 PM polprog: I have a different problem i could tackle. Figure out memory contents by sniffing the bus
05:36 PM WormFood: I have 2 ntf24l01+ units, with external antennas, and PA chip. I have them sitting less than 3 feet apart. What do you think the chances are, that I will find channels that I can't use at that distance?
05:36 PM WormFood: oh, I forgot to add, at minimum power.
05:36 PM polprog: It would probably take a simple python script but i dont have time to do it
05:37 PM polprog: if they are 2.4 ISM band id say there are a couple channels that are unusable in practice
05:37 PM WormFood: Right now, I'm adding the options to change the power levels, so I can experiment more with seeing how these things act, in potentially rf noisy environments.
05:37 PM polprog: or 5G ISM band
05:37 PM WormFood: 2.4-2.5 Ghz
05:38 PM polprog: I'd say WiFi channels can be out of the equation
05:38 PM WormFood: I'm curious to see if they'll work on more frequencies than they advertise.
05:38 PM polprog: Do you have a spectrum analyzer?
05:38 PM WormFood: I wished I did
05:39 PM WormFood: I can get a cheap one, for under $100, but it won't go up that high.
05:39 PM WormFood: I think it tops out around 900 mhz
05:39 PM polprog: Ive seen some pocket ones that span up to >2500MHz
05:39 PM WormFood: I want to get an SDR (rx and tx). That'd do the job too
05:40 PM WormFood: and at what prices?
05:40 PM polprog: Cheaper than proffesional kit, i think less than $250
05:40 PM WormFood: usually that shit is expensive. SDRs finally made it a possibility.
05:40 PM polprog: Yeah they are no Anritsu ;) random chinese touch screen tablets
05:41 PM WormFood: I mean, SDRs finally made stuff like SAs a possibility without spending 77 bazillion dollars
05:41 PM polprog: I would get a pocket one but i have a big HP one already
05:41 PM WormFood: Have you seen how many SDR modules there are?
05:41 PM polprog: I did, they are amazing
05:41 PM WormFood: They have software that will decode the old generation of satellite cell phones.
05:41 PM polprog: I wanna get a TX sdr, i only have the TV dongles and RTLSDR
05:41 PM WormFood: That's what I want.
05:42 PM WormFood: You want to send me an RTLSDR? ;)
05:42 PM polprog: It's insane (also do you mean Iridium ?)
05:42 PM WormFood: I mean, instead of throwing them away
05:42 PM WormFood: yes
05:42 PM WormFood: and for transmit, you can transmit a dvb-s signal, and pick it up on a satellite receiver.
05:42 PM polprog: I aint throwing them away (seriously tho, mine are nothing special, probably cheaper to buy them local for you)
05:43 PM polprog: Also we should make a travelling hacker box package
05:43 PM WormFood: I don't see 'em local, and it's just a want. I can't see how to make money with it, so I can't justify it.
05:44 PM polprog: For a basic sub GHz RX one you could just get a USB DVB stick
05:44 PM polprog: Most TX ones are outta reach for me too
05:44 PM WormFood: I have a dvb card....or, had one
05:45 PM polprog: $50 is a lot of money, plus shipping
05:45 PM polprog: aandrew gave me two satellite receiver PCI cards, i have to look at them
05:45 PM WormFood: I can't afford to lose $50 of my weed money ;P
05:45 PM WormFood: what kind?
05:45 PM WormFood: was one a "1020"?
05:45 PM polprog: But they probably feed the tuner output to a video IC so you cant get the raw video data
05:45 PM polprog: let me see
05:46 PM WormFood: There are 2 different types of satellite receiver cards. (I'm talking about dvb cards)
05:46 PM WormFood: You have the "expensive" and "cheap" cards.
05:46 PM polprog: Visionplus Dvb TH1022A or very similar
05:46 PM WormFood: The expensive cards have a hardware mpeg decoder
05:46 PM polprog: let me grab one actually
05:47 PM WormFood: the cheap ones do not have an mpeg decoder. I go for the cheap ones.
05:47 PM WormFood: I don't recognize that number
05:47 PM WormFood: does it say dvb-s2, or dvb-s?
05:47 PM polprog: it was mostly so you can look it up on image search
05:48 PM WormFood: The cheaper ones, can give you the ENTIRE transport stream. You can actually watch multiple videos in the same stream, at the same time.
05:48 PM polprog: doesnt say anything on it
05:48 PM polprog: theres a Connexant Fusion 878A IC
05:48 PM polprog: SM8952A
05:49 PM polprog: thats some housekeeping micro,, the connexant IC is the guts
05:49 PM WormFood: that is an upgraded model of what I have
05:49 PM polprog: https://www.linuxtv.org/wiki/index.php/Conexant_Fusion_878A
05:49 PM WormFood: which is what I suspected, when I saw that model number
05:50 PM polprog: This will go well with the LNBs im hacking
05:50 PM polprog: I wonder if i can catch Hotbird 13E without a dish
05:51 PM polprog: Like the Philips SAA7146 based DVB PCI card designs, this chipset misuses the analog video input of the chip to sample the MPEG-2 Transport Stream in video lines of the framebuffer, programming this is kind of a pain.
05:51 PM polprog: mfw
05:51 PM polprog: ok, i wonder if i can extract IQ stream from that
05:52 PM WormFood: that is interesting reading about the 878 chip
06:00 PM polprog: .. just realized i can connect the LNB to my SDR
06:00 PM WormFood: of course
06:01 PM WormFood: but, you need to also supply power to the ldb
06:01 PM WormFood: lnb
06:01 PM WormFood: 13/18 volts
06:02 PM polprog: yeah i built a bias tee last week
06:04 PM polprog: What id like to have is a reverse LNB ;)
06:06 PM rue_mohr: last version of this battery holder is pretty tight
06:29 PM * Tom_L wonders how old the kid is today
06:38 PM aandrew: WormFood: I bought a LimeSDR Mini, haven't done much with it but it's waiting for me
06:39 PM aandrew: WormFood: I think they're both 1020s, they were the ones I used for CAM stuff
06:40 PM aandrew: they are just DVB-S I think (for Dish/Bell ExpressVu before Nagra3), although I have a bunch of DVB-S2 AFEs, they will tune and spit out raw 8-bit parallel TS
06:41 PM aandrew: our old buddy tc sent them to me like 10y ago
06:43 PM polprog: yay the LNB works
06:44 PM polprog: I dont have a cable long enought to put it outside but it reacts to external factors
06:45 PM polprog: goodnight
06:50 PM WormFood: I haven't heard from tc in ages. Does he still drop by lwz?
06:51 PM WormFood: Just because he is there, doesn't mean he is active. He's there, but I haven't seen him say anything
11:54 PM rue_mohr: well I have about a month of cake left ;)
11:55 PM rue_mohr: and i didn't get to final tests of the battery holder
11:56 PM rue_mohr: I'm gonna die with so much stuff on my todo list...