This post concerns a component of a computer system being a floating point unit.
Notably from what I can find, the 8087 and 80287 FPUs do not support Sine and Cosine operations; only the 80287XL and the 80387 onwards support such operations - I am curious why.
japlytic
Badcaps Legend
Last Activity: 12-21-2023, 06:55 PM
Joined: 10-05-2005
Location: Rockhampton, Queensland, Australia
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FPU Sine and Cosine operation support
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On a related topic, [B]ESL [/B](Equivalent Series Inductance) which increases with case size which can reduce the usefulness of the capacitor to high slew-rate trensient loading - this parameter is typically not specified by manufacturers of electrolytic capacitors and I've read that in most cases, multiple electrolytic capacitors of small case size perform better than a single large case capacitor.On a related topic, [B]ESL [/B](Equivalent Series Inductance) which increases with case size which can reduce the usefulness of the capacitor to high slew-rate trensient loading - this parameter is -
Certain "Class 2" HDMI cables can be marginal at 4K 60 Hz
For some time, a "Class 2" HDMI cable (part number BN39-01583B) supplied with a Samsung 4K 60 Hz display sometimes causes the display to overlay a few horizontal lines of flickering pixels of random colours and sometimes drops out, particularly on content requring HDCP.
Since changing the cable to a thicker Class 2 unit, this problem has not occured again - do you know of other marginal "Class 2" HDMI cables supplied with displays? -
Definitions of "bus" and "interface" are distinctly different
A bus is defined as one where at least one of its signals is bidirectional (e.g. I2C, 3 wire (Select, Data IN/OUT, Clock) SPI) and an interface is where all signals are unidirectional (e.g. 4 wire SPI (Select, Data IN, Data OUT, Clock); however, certain devices can switch from a bus to an interface and vice versa e.g. Secure Digital (SD) card and certain SPI devices. -
Re: Korea Chemi-con
I've seen older Samyoung capacitors having the same shield of Chemi-Con.Leave a comment:
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LG TV recall re. bad X-class capacitors
https://[url]https://www.productsafe...erseas models.[url]https://www.productsafety.gov.au/recalls/lg-electronics-australia-pty-ltd-%E2%80%94-lg-65%E2%80%9D-and-77%E2%80%9D-smart-tvs[/url]
I can't seem to find any infomation about this problem affecting overseas models. -
SOCs with an on-die DC-DC converter
You may know this, but all Intel Core CPUs from the fourth generation (Haswell) onwards have an on-die DC-DC converter, and a System on Chip (SOC) which has such is the Broadcom BCM2835 (and certain other SOCs used in the Raspberry Pi) - the only external components for the DC-DC converter are inductor(s) and filter capacitor(s) and in some cases, feedback voltage resistor divider(s).
Do you know of any other SOCs which have an on-die DC-DC converter? -
32:9 video displays
4Air traffic control0%0Navigation0%0Surveillance0%1Video editing0%1Broadcast studio0%0Electronic billboard0%0Price lists0%0Transport timetables0%1Gaming0%1Other0%0During a browse on Amazon, I came acorss such a product and it prompted me to think of applications for them. -
Gigabyte Z690 UD AX DDR4 distingusihing failures+default video
On this motherboard with a CPU (requiring discrete graphics) supported by the BIOS (version F3) and a new video card, it has a beep code indicating a CPU failure while the onboard diagnostic LEDs indicate a video system failure and using a different motherboard of the same model had the same result despite confiriming that the new video card along with the power supply as well as the connected display/cable was operational in another system.
So therefore, I've found that the Video diagnostic LED illuminated before CPU diagnostics were performed and since the CPU has failed, video diagnostics... -
Dintek U1560 (Aosiman ASM-156UC) - touchscreen not functional
During operation of this unit, the touchscreen has stopped responding.
Here are the USB IDs which are used by this display:
27C0:0858 (which has disappeared but fortunately I obtained beforehand - touchscreen controller?)
1A40:0801 (Terminus Technology)
1A86:7523 (HL-340 USB-serial adapter)
Could it be an issue with the firmware? -
Donkey Kong Junior arcade DMA controller choice
This is about a component in a computer system being a DMA controller.
Interestingly in a circuit diagram for the Nintendo arcade game Donkey Kong Junior from 1982, even though it has a second-source Zilog Z80 compatible CPU, the DMA controller is an Intel type (8257) instead of a Zilog type.
My theory is that at the time, even though there was domestic second source manufacture for the 8257 but not (possibly) for the Zilog type DMA controller and that Nintendo (and a number of others) wanted to be loyal to their country by trying to only source components from Japanese ... -
Not all TVs can handle surround sound on a HDMI input
With a home theatre PC connected to a TV via HDMI, Windows reveals that the TV only supports stereo sound even though the TV has a HDMI ARC connection to an AV receiver which is powered on; I also had an issue that the AV receiver does not always retain the input setting for routing the HTPC video through to the TV in standby.
So I connected a second HDMI cable to the HTPC and set it to duplicate the video outputs, but I had random audio dropouts when playing content with surround sound being passed to the AV receiver (dropouts did not occur when I replayed the content where it dropped... -
Motherboard diagnostic LED states
I've identified no more than 16 possible states for indication of motherboard diagnostic states which can be indicated with only 4 single colour LEDs which is:
[LIST][*]No power applied (all off)[*]Power applied - no standby to RAM (one is on)[*]Standby to RAM[/LIST]
In sequence after power on not waking from standby to RAM:[LIST][*]Power supply rail(s) missing or out of tolerance (includes CPU +12V)[*]Power supply protection shutdown (trap - also display before boot)[*]Onboard DC-DC converter failure (includes CPU DC-DC converter)[*]CPU failure[*]BIOS checksum failure[*]Platform... -
Re: Delta AC-106A (Dell P/N 00G8CN) DC-DC converter repurposing
I used a server PSU with a +12V output as an input with this output being switched along with the +3.3/+5V DC-DC converters....Leave a comment:
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Delta AC-106A (Dell P/N 00G8CN) DC-DC converter repurposing
This unit from a Dell PowerEdge R320/R420 has +3.3V/22A and +5V/22A DC-DC converters (one for each rail) which is a good candidate for conversion to a 12V input ATX PSU.
Diagrams of required modifications regarding starting of the DC-DC converters is included with code at [url]http://github.com/brycecherry75/ServerPSUtoATX[/url] which mentions required pullup/pulldown resistor placements and if required, simple level translators in the sketch.
How to test protections:
Overvoltage: Short (3.3V/5V)OVP pad to TEST_SGND
Undervoltage: Short (3.3V/5V)UVP to its respective... -
Certain DisplayPort-HDMI cables can disable HDMI CEC communication
With a setup including a TV and AV receiver where HDMI Consumer Electronics Control (CEC) and Audio Return Channel (ARC) functions were working, these two functions stopped working after changing some connections (not the one between the AV receiver and TV), so I believed it was a corrupt setting in the AV receiver or TV, but when I disconnected a passive DisplayPort-HDMI cable (which a Multimode DisplayPort connector supports HDMI with a low cost passive cable or adaptor) connected to a home theatre PC, HDMI CEC and ARC functionality was restored.
An examination of the HDMI CEC wiring... -
TPM 2.0 is not always standard issue
A Gigabyte Z690 motherboard I have recently purchased had a connector for the TPM (Trusted Platform Module) but was not included as standard in the box even though Windows 11 (which requires it) has been released a couple of months ago.
I've read that the TPM is included as standard for certain regions as well. -
Re: help to find Nippon Chemi-Con datasheet
According to the information you provided, this is a general purpose unit.Leave a comment:
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Re: Test equipment and 1PPS inputs
Although not a piece of test equipment (but a piece of digital communications equipment), a Tandberg MT5600 DVB-T modulator can have the internal reference oscillator disciplined by a 1PPS input.Leave a comment:
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HEP Group LBVC9BI UNI LED driver
This unit had approximately 50K running hours before it failed; upon opening, a bulging (and heat stressed) TK UTWHM series 450V 10uF unit caused the TOP278 IC to blow its top off.
Other electrolytic capacitors were a 25V 680uF Taicon HH (output filter) and 22uF 50V Hermei LR (driver circuit), both of which have not failed....
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