Is there such thing as a 4 bit CRC ?

Started by boB in comp.arch.embedded5 months ago 35 replies

If I create a 1 byte command that only uses 4 bits for 16 different functions, and there were NO following bytes (there might be...

If I create a 1 byte command that only uses 4 bits for 16 different functions, and there were NO following bytes (there might be folling bytes for some CMDs), I was thinking that the lower 4 bits could be used for error detection. Could of course just truncate an 8 bit CRC I suppose and place it there. Just thought I would ask. Never thought of only 4 bits before but sometimes a ...


Looking for uC/OS-II companion CD

Started by szamos in comp.arch.embedded6 months ago 1 reply

Hi, I have the "MicroC/OS-II The Real Time Kernel" book (2nd ed), but since I bought it used, it came without the companion CD. Does...

Hi, I have the "MicroC/OS-II The Real Time Kernel" book (2nd ed), but since I bought it used, it came without the companion CD. Does anyone have the companion CD, or know where to get it? I looked on Micrium's website, and while they have many downloadable files, this one is not one of them. TIA My con-ned email address can be corrected by removing - and changing one other cha...


assembly language/masm32

Started by Razvan Mihalcea in comp.arch.embedded6 months ago 2 replies

I need some help for an exam on friday morning using assembly language if any1 can help me.

I need some help for an exam on friday morning using assembly language if any1 can help me.


RPC/RMI in heterogeneous environments

Started by Don Y in comp.arch.embedded6 months ago 14 replies

I postpone automatic type conversion to the *servant*, rather than embedding it in the client-side stub. My reasoning is that this allows a...

I postpone automatic type conversion to the *servant*, rather than embedding it in the client-side stub. My reasoning is that this allows a wider window for the targeted node to change *after* the RPC/RMI invocation and before it's actual servicing. I.e., it would be silly to convert arguments for a target node of type X, marshall them and then, before actual transport, discover that the ...


Slow (industrial?) SD cards

Started by Theo in comp.arch.embedded6 months ago 2 replies

I have a setup with a micro SD card which may be suffering signal integrity issues. One suggested remedy is to try it with a slower card. I...

I have a setup with a micro SD card which may be suffering signal integrity issues. One suggested remedy is to try it with a slower card. I had some success with a 2GB Class 2 card from the dark ages, but 2GB is too small to test properly. There's nothing I can really change about the setup - it appears the speed selection is happening in ROM, so if I put in a fast card the faster speeds...


Fixed Point Calculations

Started by Rick C in comp.arch.embedded6 months ago 16 replies

I'm working with a custom designed hardware in fixed point arithmetic. I expect it won't be too difficult once I get my head wrapped around it,...

I'm working with a custom designed hardware in fixed point arithmetic. I expect it won't be too difficult once I get my head wrapped around it, but I seem to be spinning my wheels getting started. The arithmetic hardware has an 18x18 multiplier producing a 36 bit result feeding a three input, 55 bit adder. The other two inputs are a 54 bit input that is subtracted and a loopba


Taking COVID Seriously

Started by Rick C in comp.arch.embedded7 months ago 12 replies

Wow, some outfits do take the disease seriously. I need to get some boards from my customer to modify and return to test which could all be done...

Wow, some outfits do take the disease seriously. I need to get some boards from my customer to modify and return to test which could all be done on the same day since everyone involved is a few blocks apart if I hand carry the boards. My customer says they are not allowed to have anyone in anymore... at all! So I guess we'll have to do this via shipping boards around and spend


Ancient Yocto enforced by board manufacturer - "repo init" doesn't work

Started by Wojciech Zabolotny in comp.arch.embedded7 months ago 2 replies

Hi, I need to build Linux for Congatec QMX8 SMARC SBC. The procedure is described...

Hi, I need to build Linux for Congatec QMX8 SMARC SBC. The procedure is described here: https://wiki.congatec.com/display/IMX8DOC/conga-QMX8+Yocto+2.5 It requires Ubuntu 2016.04, so I have created a virtual machine for it. Unfortunately, the "repo init" doesn't work. I get the following error: gpg: keyring `/home/dev/.repoconfig/gnupg/secring.gpg' created gpg: keyring `/home/dev/.repoc...


Good Hardware Tools

Started by Rick C in comp.arch.embedded7 months ago 80 replies

I will be working from home to help an open ventilator project and want to acquire some tools. I've needed a new scope for some time, but want an...

I will be working from home to help an open ventilator project and want to acquire some tools. I've needed a new scope for some time, but want an attached scope using the PC for a display. They are no cheaper than the full scopes and good ones may be more expensive. The only ones I've found that are decent are the Pico Technology scopes. Rather pricey. Then there are small l


TC358749 HDMI-CSI bridge supported in new kernels?

Started by Wojciech Zabolotny in comp.arch.embedded7 months ago 1 reply

I have a few boards with Toshiba's TC358749 HDMI to CSI bridge. It is supported by a tc35874x.c driver, available e.g.,...

I have a few boards with Toshiba's TC358749 HDMI to CSI bridge. It is supported by a tc35874x.c driver, available e.g., here: https://github.com/54shady/qop_kernel/blob/master/drivers/media/i2c/tc35874x.c However, the new kernels have only the tc358743.c driver - https://elixir.bootlin.com/linux/latest/source/drivers/media/i2c/tc358743.c There is no information if it also supports the old TC3...


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