Recent Posts

1

Projects, Designs, and Technical Stuff / Re: Corrosion on DIP pins

« Last post by rsjsouza on Today at 10:50:35 am »

Assuming there was no ingress of any kind, as mentioned before the manufacturing of the computer might have either scratches some parts or left residue that slowly corroded over the decades. I have seen many boards like that.

One additional point is that there were crap and good leadframes as well especially from that era (1970s-1980s), even with parts from the same manufacturer but different lots or country of origin. Standards for handing and storage of ICs were still being developed.

Just an additional annoyance: MOSTEK is known nowadays to have a relatively high incidence of memory rot, which renders the IC unusable due to internal degradation even on ICs that are physically in good shape.

Good luck in your repair/restoration!

2

Embedded Computing / Re: Is it possible to read AHCI registers using setpci on Linux?

« Last post by magic on Today at 10:46:48 am »

AFAIK setpci only access the configuration address space of PCI. If the registers you are looking for are there then you are set. If they are in some MMIO region, I don't see a way of reading them with setpci.

However, the related lspci (with -v flag) will tell you where the MMIO registers are mapped in the CPU physical address space. Knowing this, you could presumably read them by means of /dev/mem or something like that (note: in recent times there were some attempts to restrict or completely remove this mechanism on security grounds and I'm not sure how it works in mainstream distributions these days).

3

Beginners / Re: Comparator circuit seems to be oscillating (well, pulsing, really). Solutions?

« Last post by Tandogan on Today at 10:35:38 am »

Hi

I need your help.

I have checked the capacitors on my digital piano and got the following results in ESR levels. I used the peak ATLAS ESR70 gold.

10000 uF 25V - ESR 0.01
2200 uF 25V - ESR 0.02
470 uF 10V - ESR 0.20
100 uF 25V - ESR 0.43
47 uF 16V - ESR 0.64
10 uF 16V - ESR 1.01
1 uF 50V - ESR 1.10

I am especially suspicious about ther results for 10 micro and 1 micro F. They should be around 8 and 5 respectively. Do these results mean that I need to change the 10 micro and 1 micro D capacitors?

Thanks for your replies.
Tan

4

Mechanical & Automation Engineering / Repurposing PVC Pipe for DIY Projects

« Last post by jonovid on Today at 10:28:37 am »

looks like a good Idea for one of a kind electronics enclosures , modified power tools or battery box's

what type of PVC glue would you recommend for this? as it must melt the PVC laminate sheets into one solid block without delamination over time .

5

Microcontrollers / Re: How to create custom bootloader in esp8266

« Last post by mianos on Today at 10:24:43 am »

Thank you for taking the time to answer my question. I was wondering if there would be any problems booting the program if the power goes out while updating the ESP8266 firmware?

Generally you set up different partitions to store the OTA. Generally it's not possible to write to the running application as you update it.
If the flash fails, it does not affect the existing application. You can just reboot and try again.

Keeping in mind, a lot of this depends on how much flash you have.
https://github.com/espressif/ESP8266_RTOS_SDK/tree/master/examples/system/ota/simple_ota_example

Also, the OTA updater is not part of the boot system. It needs the tcp ip stack that is way way later. To implement OTA you generally set it up and organise a permanent thread to listen for the OTA or you can poll the OTA socket if you you are using a toy stack over the top of the RTOS, like the Arduino wrapper.

There are several Arduino wrappers for OTA systems for the 8266. They mostly work OK. For example the OTA for the Tasmota project is very reliable and uses multiple partitions with fall back so if it fails it's no big deal to just try again, not having to resort to connecting the USB up and flashing it via serial.

May I suggest, you also look at the esp32, for which there is much better support now and it's about the same price. I think the C3 is now 10c cheaper than than the 8266 in volume.

6

Repair / Re: Looking for a small PCB-mount microswitch with a long stem

« Last post by Phaseseeker on Today at 10:19:41 am »

That's exactly what I was looking for. Thanks!

7

Embedded Computing / Re: Is it possible to read AHCI registers using setpci on Linux?

« Last post by RoGeorge on Today at 10:13:42 am »

I don't know to answer the question, but the Linux kernel should have a Device Tree (DT).  The DT is telling the kernel (at boot), what driver to load for each device, and any specific parameters the driver might need.  Later, that DT is mapped into a directory tree (in Linux, everything is a file), here mapped at /proc/.

For example, if I search for PCI in /proc/ of my desktop PC, there is a /proc/bus/pci/ directory, and a /proc/bus/pci/devices file.  Inside that file there is a line contaning the text ahci, and some addresses/registers.

See if you can make use of any of that info, in order to find the address you are interested in, though never tried that myself.

No idea if this could help changing the settings you are after, if it applies to your OS flavor, or if it brings anything extra other than setpci can already do/show (I don't know much about setpci).  But if it does, then it should be possible to decompile the (binary) device tree that is in use, edit the decompiled DT to add your changes in the DT sources, then recompile the DT (the decompiler/compiler is called dtc), so to make your changes persistent after a reboot.

8

Manufacturing & Assembly / Re: Advice on adding missing parts to an assembled board

« Last post by Aspartame on Today at 10:08:57 am »

I had the same issue with JLCPCB when they had stopped assembling esp32-wroom-32e module with the economy pcba service. I mounted the wroom module using a hot plate. I applied solder to the pads using a soldering iron in advance.

9

Microcontrollers / Re: Divide clock by 3 on a ATF16V8B

« Last post by xvr on Today at 10:05:56 am »

No, it's impossible.
VHDL code use triggers with positive and negative clock edges. ATF16V8B have only positive clocked triggers.
You can create simple divider by 3 on it, but you've got not symmetrical output (with duty cycle 1//3 or 2/3 - on your choice)
And for ATF you need a special programmer (hardware), do you need any?

10

Microcontrollers / Re: How to create custom bootloader in esp8266

« Last post by xvr on Today at 09:58:59 am »

> I was wondering if there would be any problems booting the program if the power goes out while updating the ESP8266 firmware?

No program - no problem  It just will not start, only builtin bootloader will survive