Search found 85 matches

by rstofer
Fri Jun 10, 2005 10:40 am
Forum: General Discussion
Topic: pic pwm feasible?
Replies: 7
Views: 1762

Re: pic pwm feasible?

So, you are just doing digital to analog conversion with parallel output.<p>There are more than 561,000 hits on Google for 'parallel digital to analog conversion', without the quotes.<p>No big deal but, for the number of pins and external components, you don't get anywhere near the resolution. Almos...
by rstofer
Tue Jun 07, 2005 5:31 pm
Forum: General Discussion
Topic: voltage dropping
Replies: 5
Views: 1225

Re: voltage dropping

I would caution you against doing any work on an elevator or any other device where life safety can be an issue. Get a licensed company to do whatever is necessary to find a permanent solution - even if it means a new control panel.<p>If you are in the US, you should run away from this problem as fa...
by rstofer
Sat Jun 04, 2005 2:32 pm
Forum: General Discussion
Topic: RS-485 Phone Dialer
Replies: 4
Views: 1172

Re: RS-485 Phone Dialer

This one http://homesecuritystore.com/detail_pages/ad2001.htm meets almost none of your criteria. However, it is a 2 input device that can call 4 different numbers and leaves either a numeric or voice message.<p>I bought it for use on my boat. It could dial my home phone (voice), cell phone (voice) ...
by rstofer
Wed Jun 01, 2005 10:41 pm
Forum: General Discussion
Topic: digital to RS-232
Replies: 6
Views: 1503

Re: digital to RS-232

Ah, but you said "polled". How do you intend to implement polling? Sure the UARTs will convert parallel to serial and the driver chip will change it to RS232 but something has to cause the UART to send data.<p>It would be pretty easy to connect a 555 timer to continuously strobe the UART so it will ...
by rstofer
Wed Jun 01, 2005 9:46 pm
Forum: General Discussion
Topic: FFT chipset
Replies: 3
Views: 905

Re: FFT chipset

Sure, this is a popular application for FPGAs. See http://www.xilinx.com/ipcenter/catalog/logicore/docs/c_fft1024_v1_0.pdf or http://www.opencores.org/browse.cgi/by_category <p>The Xilinx document is describing an IP Core (Intellectual Property) which they sell/license for use in their chips. It is ...
by rstofer
Mon May 30, 2005 7:03 pm
Forum: General Discussion
Topic: Books on Op-Amps
Replies: 9
Views: 2095

Re: Books on Op-Amps

Try this: "Op Amps For Everyone" a free book from TI http://focus.ti.com/docs/apps/catalog/r ... e=slod006b<p>I can't tell you how much help I have gotten from Chapter 4. I quote that material every chance I get.
by rstofer
Mon May 30, 2005 2:55 pm
Forum: General Discussion
Topic: 8085 IDE
Replies: 14
Views: 3272

Re: 8085 IDE

There is no doubt that I am strongly in the Atmel ATmega128 camp having essentially defected from the PIC world. I like the hardware and the AVR Lib stuff is great. Just not having to deal with memory issues does it for me.<p>That said, I would still consider anything that could run 8080 code just s...
by rstofer
Mon May 30, 2005 9:56 am
Forum: General Discussion
Topic: Choosing a microcontroller platform
Replies: 16
Views: 3131

Re: Choosing a microcontroller platform

This is another Atmel based controller. It is quite inexpensive considering http://www.digilentinc.com/info/cerebot.cfm
by rstofer
Sun May 29, 2005 2:59 pm
Forum: General Discussion
Topic: Choosing a microcontroller platform
Replies: 16
Views: 3131

Re: Choosing a microcontroller platform

First, I stand corrected, the Z8 does have a lot of internal gadgets.<p>Second, the ATmega: either way, you can program the boards with ISP or JTAG. I'm not sure of my facts here but it seems that if you buy the MAVRIC kit you may have to use JTAG to set the fuses to enable ISP. I read the chip docu...
by rstofer
Sun May 29, 2005 1:59 pm
Forum: General Discussion
Topic: Choosing a microcontroller platform
Replies: 16
Views: 3131

Re: Choosing a microcontroller platform

I forgot to mention: the ATmega128 is FAST. One short instruction per clock at 16 MHz or about 16 MIPS! More than 3 times the speed of the 16Fxx PICs. With instruction set differences, I wouldn't be surprised to find it 6 times as fast on a real program.
by rstofer
Sun May 29, 2005 1:57 pm
Forum: General Discussion
Topic: Choosing a microcontroller platform
Replies: 16
Views: 3131

Re: Choosing a microcontroller platform

I don't think you will find the specialized hardare inside the Zilog Z8.<p>Let me offer another suggestion. Look at Atmel, particularly the ATmega128. Here you will have 128k of flash for program storage and 4k of SRAM for data. And it has ALL of the gadgets - in depth.<p>Take a look over at www.spa...
by rstofer
Sat May 28, 2005 10:46 am
Forum: General Discussion
Topic: What is this called?
Replies: 10
Views: 2285

Re: What is this called?

Gating a clock input to a flop can lead to interesting behavior.<p>I haven't used PALs because I don't want to invest in programmers. However, CPLDs are a lot more friendly to hobbyists.<p>For a project with a clock, 8 inputs and 8 (or 16) output, 3 or 4 dips is probably the way to go. If there is m...
by rstofer
Sat May 28, 2005 10:11 am
Forum: General Discussion
Topic: US made chip is cheaper in China, why?
Replies: 14
Views: 3513

Re: US made chip is cheaper in China, why?

For quantity 1, the price difference is unimportant. $1, $3, $5 - it just doesn't matter. Relative to the perceived cost of labor, component cost is insignificant. In my case, there is no real cost of labor; I am retired.<p>What matters is a device that is known to have passed final test from a repu...
by rstofer
Sat May 28, 2005 6:37 am
Forum: General Discussion
Topic: US made chip is cheaper in China, why?
Replies: 14
Views: 3513

Re: US made chip is cheaper in China, why?

Few 'run of the mill' devices are manufactured in the US. There are huge foundries in Taiwan and Singapore (and probably China) where the entire device is manufactured. It is more typical to manufacture the state of the art wafers in the US until the process is well understood and to then send the p...
by rstofer
Fri May 27, 2005 8:13 pm
Forum: General Discussion
Topic: US made chip is cheaper in China, why?
Replies: 14
Views: 3513

Re: US made chip is cheaper in China, why?

Another way to look at cost is in terms of a percentage of income. At $1.80 against an income of $1200/mo it represents 0.125%. At $3.50 against an income of, say, $8000/mo. it represents 0.04375%. So it costs about 1/3 as much as much here as there. The numbers aren't important, it is the number of...