Comments for Embedded Insights Channels http://www.embeddedinsights.com/channels Shedding Light on the Hidden World of Embedded Systems Mon, 28 Jul 2014 16:18:37 -0400 hourly 1 http://wordpress.org/?v=3.0 Comment on Are you, or would you consider, using a 4-bit microcontroller? by Lutz http://www.embeddedinsights.com/channels/2010/11/24/are-you-or-would-you-consider-using-a-4-bit-microcontroller/#comment-228544 Lutz Mon, 28 Jul 2014 16:18:37 +0000 http://www.embeddedinsights.com/channels/?p=388#comment-228544 Motorola formerly has set ZRHC4 as an most competetive 4bit mcu however today nobody knows anout that Motorola formerly has set ZRHC4 as an most competetive 4bit mcu
however today nobody knows anout that

]]> Comment on Do you ever think about endianess? by Jeet http://www.embeddedinsights.com/channels/2012/02/08/do-you-ever-think-about-endianess/#comment-175439 Jeet Fri, 21 Mar 2014 21:41:05 +0000 http://www.embeddedinsights.com/channels/?p=687#comment-175439 Hi, you wrote: Despite the C language standard do not specify endianness, you can write C code that is completely endian-insensitive also. The problems arise when you assume some object representation and access types under the hood, like using unions or pointer casts to get the chars under floats or ints. What are some techniques to deal with this issue as I am currently trying to write a communications module using Modbus. If the struct containing ints, floats etc is typecasted to chars for Tx/Rx, how to dynamically detect a variable change and thus a required byte swap? Thanks! Jeet Hi, you wrote: Despite the C language standard do not specify endianness, you can write C code that is completely endian-insensitive also. The problems arise when you assume some object representation and access types under the hood, like using unions or pointer casts to get the chars under floats or ints.

What are some techniques to deal with this issue as I am currently trying to write a communications module using Modbus. If the struct containing ints, floats etc is typecasted to chars for Tx/Rx, how to dynamically detect a variable change and thus a required byte swap?

Thanks!
Jeet

]]> Comment on Are you, or would you consider, using a 4-bit microcontroller? by lol http://www.embeddedinsights.com/channels/2010/11/24/are-you-or-would-you-consider-using-a-4-bit-microcontroller/#comment-162334 lol Thu, 30 Jan 2014 03:23:05 +0000 http://www.embeddedinsights.com/channels/?p=388#comment-162334 I've got one! (in my electric toothbrush): http://www.youtube.com/watch?v=JJgKfTW53uo I’ve got one! (in my electric toothbrush):

http://www.youtube.com/watch?v=JJgKfTW53uo

]]> Comment on To MMU or not to MMU? by BP http://www.embeddedinsights.com/channels/2010/07/21/to-mmu-or-not-to-mmu/#comment-123953 BP Wed, 02 Oct 2013 22:26:16 +0000 http://www.embeddedinsights.com/channels/?p=215#comment-123953 All MMU entries can be locked. Also, most MMU tables do not have to be several levels deep. It is entirely possible to fit an entire system description within the TLB (translation look-aside buffer). It is also possible to write embedded software in C++. It is just more complex. I think that the arguments are the same; with perhaps more benefits to use an MMU. Perhaps when people say MMU, they believe that it must have 'page faults', etc. The only time the 'page fault' should occur in a statically configured embedded system is when some code is not addressing memory that it owns. It is also quite easy to lock the MMU entries in the interrupt path. Too bad people seem so negative about this post. Thanks for trying Robert. All MMU entries can be locked. Also, most MMU tables do not have to be several levels deep. It is entirely possible to fit an entire system description within the TLB (translation look-aside buffer). It is also possible to write embedded software in C++. It is just more complex. I think that the arguments are the same; with perhaps more benefits to use an MMU. Perhaps when people say MMU, they believe that it must have ‘page faults’, etc. The only time the ‘page fault’ should occur in a statically configured embedded system is when some code is not addressing memory that it owns. It is also quite easy to lock the MMU entries in the interrupt path. Too bad people seem so negative about this post. Thanks for trying Robert.

]]> Comment on The Express Traffic Lane (It’s Not the Computer, It’s How You Use It) by Ed Stark http://www.embeddedinsights.com/channels/2010/09/24/the-express-traffic-lane-it%e2%80%99s-not-the-computer-it%e2%80%99s-how-you-use-it/#comment-28295 Ed Stark Tue, 09 Oct 2012 00:41:05 +0000 http://www.embeddedinsights.com/channels/?p=324#comment-28295 So if i am understanding this correctly, if i have a passenger and do not remove the transponder then i am charged the prevailing toll. is this correct? On the flip side, if i am a single occupant how does the system know except visually by a police officer? So if i am understanding this correctly, if i have a passenger and do not remove the transponder then i am charged the prevailing toll. is this correct?

On the flip side, if i am a single occupant how does the system know except visually by a police officer?

]]> Comment on To MMU or not to MMU? by true_toyou http://www.embeddedinsights.com/channels/2010/07/21/to-mmu-or-not-to-mmu/#comment-20888 true_toyou Sat, 11 Aug 2012 09:06:06 +0000 http://www.embeddedinsights.com/channels/?p=215#comment-20888 how about use MMU+Dcache? as you know, when the MMU is disabled, the Dcache also couldn't be used. So if we use the MMU, and enable the Dcache, will the performance be better than no MMU and no Dcache? how about use MMU+Dcache?
as you know, when the MMU is disabled, the Dcache also couldn’t be used. So if we use the MMU, and enable the Dcache, will the performance be better than no MMU and no Dcache?

]]> Comment on Are random numbers a solved function? by C.L. @ LI http://www.embeddedinsights.com/channels/2012/03/07/are-random-numbers-a-solved-function/#comment-16825 C.L. @ LI Sun, 27 May 2012 16:22:55 +0000 http://www.embeddedinsights.com/channels/?p=702#comment-16825 @Ray - I agree mostly, but when it comes to manufacturing of devices and properly provisioning them for exclusive, protected use with services at a later time, the black-hat argument is moot. So I'm with Emilio - it's all about context. In the wild, hackers will do their thing, but to sell a product that supports various DRM schemes, for instance, so you can make money on services later - an entropy register in an SoC will typically suffice as a starting point for a security model, and will definately be better than a PRNG. Please note I said a starting point. Proper provisioning and use of OTP fuses is also pretty vital. If your manufacturing line doesn't have a V&I station at board level test to ensure that rails are properly biased and you can't shell out the cash for proper enclosures to block out UV and EMI during manufacturing, you definately have not only a system security issue on your hands but a pretty severe OPS process issue and I would want to buy the product or sign up as a partner to deliver content on the device. @Ray – I agree mostly, but when it comes to manufacturing of devices and properly provisioning them for exclusive, protected use with services at a later time, the black-hat argument is moot. So I’m with Emilio – it’s all about context. In the wild, hackers will do their thing, but to sell a product that supports various DRM schemes, for instance, so you can make money on services later – an entropy register in an SoC will typically suffice as a starting point for a security model, and will definately be better than a PRNG. Please note I said a starting point. Proper provisioning and use of OTP fuses is also pretty vital.

If your manufacturing line doesn’t have a V&I station at board level test to ensure that rails are properly biased and you can’t shell out the cash for proper enclosures to block out UV and EMI during manufacturing, you definately have not only a system security issue on your hands but a pretty severe OPS process issue and I would want to buy the product or sign up as a partner to deliver content on the device.

]]> Comment on Do you ever think about endianess? by L.H. @ LI http://www.embeddedinsights.com/channels/2012/02/08/do-you-ever-think-about-endianess/#comment-16824 L.H. @ LI Sun, 27 May 2012 16:22:06 +0000 http://www.embeddedinsights.com/channels/?p=687#comment-16824 IBM 360 and derivatives are big endian as far as structure fields with bit fields, they are reversed IBM 360 and derivatives are big endian

as far as structure fields with bit fields, they are reversed

]]> Comment on Do you ever think about endianess? by J.P. @ LI http://www.embeddedinsights.com/channels/2012/02/08/do-you-ever-think-about-endianess/#comment-16658 J.P. @ LI Tue, 22 May 2012 15:44:11 +0000 http://www.embeddedinsights.com/channels/?p=687#comment-16658 Htonl, htons, ntohl, ntohs are your best friends, and both bitfields and struct padding are typically compiler-dependent. Htonl, htons, ntohl, ntohs are your best friends, and both bitfields and struct padding are typically compiler-dependent.

]]> Comment on Eclipse and NetBeans replacing embedded IDEs (part 2) by Peter http://www.embeddedinsights.com/channels/2012/05/17/eclipse-and-netbeans-replacing-embedded-ides-part-2/#comment-16622 Peter Mon, 21 May 2012 19:35:29 +0000 http://www.embeddedinsights.com/channels/?p=723#comment-16622 There are hundreds of applications on the NetBeans Platform, just to clarify, even though there might be one in the embedded space, there are certainly many many others in many other software development spaces: http://platform.netbeans.org/screenshots.html There are hundreds of applications on the NetBeans Platform, just to clarify, even though there might be one in the embedded space, there are certainly many many others in many other software development spaces:

http://platform.netbeans.org/screenshots.html

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