标签: EPROM

Swaziland is an absolute monarchy in a rather dry area of Southern Africa. As part of a United Nations project to irrigate sugar cane fields, a dam was built on a river that flowed from Swaziland to Mozambique. Because the water flowed across an international border, there was a bilateral agreement as to how much water was to be released from the dam. The amount to be released was also a function of the inflow to the dam.   In order to measure the water flow, a weir was built consisting of a concrete base with a stepped steel profile set into it. The water level, coupled with the cross sectional area of the weir, together with some hydrological tables determined the water flow. Of course, there were several rivers and streams to be measured. I was contracted to build the microcomputer that measured the water level and transmitted the data, via a repeater station on a nearby hilltop, to the central computer behind the dam wall in the control centre. The outstation was based around the 80C35 (an 8748 minus the EPROM) because -- in those days -- there were no complete single chip CMOS micros. The repeater was 8748 controlled.   Note the IC superstructure in the middle. National Semiconductor apparently never had access to EPROM technology, so they created the 87P50, which was an 8748 with a piggyback EPROM allowing from 1Kbytes to 4Kbytes to be plugged in.   The central computer (which I also programmed) was based on an Intel Multibus system running an 8085, which displayed the hydrological data on a Lear Siegler "dumb" terminal (all of this took place in the early 1980s).   In order to calculate the water flow, I created a lookup table, which was obviously finite. I asked the question as to what happened when the water rose above the maximum specified and what message should I display. I was told that this could never happen. In fact, I was told that this was so unlikely I could display the message: "THE KING IS A ****" (expletive deleted). Well, I was rather more genteel back in those days, so I opted to display "FLOOD!" instead.   At the time we completed the project, there had been a drought, and this continued until the area was hit by tropical cyclone Domoina in 1984. This incredible weather system dropped 50cm (20") of rain in a 36-hour period. The 135 MCM (million cubic metres) Mnjoli dam went from 0 to 100% in less than 20 hours. The dam had an earth wall, and if water flows over the top of this structure, that that is the end of the dam. In the event, they evacuated the control centre when all eight stations were reading "FLOOD!" Fortunately, the design of the overflow channels managed to cope, and a greater disaster was averted.   The screen output during development.   In the aftermath, it turned out that all of the water level stations had been completely washed away and the whole system had to be replaced. If I had followed the original advice I was given, I wouldn't have been able to return.   Have you ever made the mistake of believing what you were told? And has any of your work been destroyed by major natural event?   Aubrey Kagan Engineering Manager Emphatec

K1200并口编程器（烧写器）的元件分布和willem EPROM编程器原理图 wxleasyland@sina.com 2013.6.2   多年前邮购了一块K1200并口编程器（附带一个89C51转换板），可烧写很多ROM芯片。我只用来烧单片机89C51和2051，很少用。 最近想用一下89C51单片机，结果烧写时，发现提示出错，不知道故障在哪。 编程器上的芯片型号全刮掉了，不知道是什么，只能硬着头皮去分析。 K1200是基于Willem EPROM Programmer来做的，手上只有WILLEM PCB4.5版的原理图。 网上找了很久很久，找不到什么资料，K1200的网站也已经打不开了，WILLEM的网站也打不开了。 只是找到大概K1200与WILLEM PCB 5.5版很接近，但网上图片上也是擦掉了芯片型号。而且也找不到5.5版的原理图，现在WILLEM资料太少了，可能大家都不用这种并口的编程器了吧。 于是这几天硬着头皮对K1200分析了下，双面板分析电路真的很麻烦。 发现K1200基本电路与WILLEM 4.5版比较接近，芯片型号基本都找出来了，右边有个芯片没有去细分析，可能是4066，不管它了，因为用不上。 K1200编程器的元件分布如下： WILLEM PCB4.5的原版电路如下：   发现烧写电压由34063生成为12.4V，通过LM324导通后，少了1.5V，变成10.9V，然后又经过一个二极管，变成了10.3V。 是不是烧写电压不够，造成烧写不成功？于是对K1200附带的89C51转换板进行改造，加上一个7812，在烧写时，K1200主板上的烧写电压调成15V，这样经过这个7812，就是正确的12V了。 然后再试，发现烧写了还是出错，看来不是烧写电压的问题。   于是，调大软件上的“脉宽”和“延时”，脉宽可能是PROG脚的低电平脉冲宽度，延时可能是烧写电压VPP的脉冲宽度。结果，烧写成功了！！可能是计算机并口的差异造成的。 不折腾了，因为现在都改用STC单片机，直接串口在线烧写就行，方便多了。  

Here's a quote from Bjarne Stroustrup: I have always wished that my computer would be as easy to use as my telephone. My wish has come true. I no longer know how to use my telephone. Everyone knows how Intel invented the computer on a chip in 1971, introducing the 4004 in an ad in a November issue of Electronic News. But everyone might be wrong. TI filed for a patent for a "computing systems CPU" on August 31 of that same year. It was awarded in 1973 and eventually Intel had to pay licensing fees. It's not clear when they had a functioning version of the TMS1000, but at the time TI engineers thought little of the 4004, dismissing it as "just a calculator chip" since it had been targeted to Busicom's calculators. Ironically the HP-35 calculator later used a version of the TMS1000. But the history is even murkier. The existence of the Colossus machine was secret for almost three decades after the war, so ENIAC was incorrectly credited with being the first useful electronic digital computer. A similar parallel haunts the first microprocessor. Grumman had contracted with Garrett AiResearch to build a chipset for the F-14A's Central Air Data Computer. Parts were delivered in 1970, and not a few historians credit the six chips comprising the MP944 as the first microprocessor. But the chips were secret until they were declassified in 1998. Others argue that the multi-chip MP944 shouldn't get priority over the 4004, as the latter's entire CPU did fit into a single bit of silicon. In 1969 Four-Phase Systems built the 24bit AL1, which used multiple chips segmented into 8bit hunks, not unlike a bit-slice processor. In a patent dispute a quarter century later proof was presented that one could implement a complete 8bit microprocessor using just one of these chips. The battle was settled out of court, which did not settle the issue of the first micro. Then there's Pico Electronics in Glenrothes, Scotland, which partnered with General Instruments (whose processor products were later spun off into Microchip) to build a calculator chip called the PICO1. That part reputedly debuted in 1970, and had the CPU as well as ROM and RAM on a single chip. Clearly the microprocessor was an idea whose time had come. Japanese company Busicom wanted Intel to produce a dozen chips that would power a new printing calculator, but Intel was a memory company. Ted Hoff realised that a design with a general-purpose processor would consume gobs of RAM and ROM. Thus the 4004 was born. It was a four-bit machine packing 2,300 transistors into a 16-pin package. Why 16 pins? Because that was the only package Intel could produce at the time. Today fabrication folk are wrestling with the 22nm process node. The 4004 used 10,000-nm geometry. The chip itself cost about $1,100 in today's dollars, or about half a buck per transistor. CompUSA currently lists some netbooks for about $200, or around 10 microcents per transistor. And that's ignoring the keyboard, display, 250-GB hard disc, and all the other components and software that go with the netbook. Though Busicom did sell some 100,000 4004-powered calculators, the part's real legacy was the birth of the age of embedded systems and the dawn of a new era of electronic design. Before the microprocessor, it was absurd to consider adding a computer to a product; now, in general, only the quirky build anything electronic without embedded intelligence. At first even Intel didn't understand the new age they had created. In 1952 Harold Aiken figured a half-dozen mainframes would be all the country needed, and in 1971 Intel's marketing people estimated total demand for embedded micros at 2,000 chips per year. Federico Faggin used one in the 4004's production tester, which was perhaps the first commercial embedded system. About the same time the company built the first EPROM and it wasn't long before they slapped a microprocessor into the EPROM burners. It quickly became clear that these chips might have some use after all. Indeed, Ted Hoff had one of his engineers build a video game—Space War—using the four-bitter, though management felt it was a goofy application with no market. In parallel with the 4004's development, Intel was working with Datapoint on a computer, and in early 1970, Ted Hoff and Stanley Mazor started work on what would become the 8008 processor. 1970 was not a good year for technology; as the Apollo program wound, down many engineers lost their jobs, some pumping gas to keep the families fed. (Before microprocessors automated the pumps, gas stations had legions of attendants who filled the tank and checked the oil. They even washed windows.) Datapoint was struggling, and eventually dropped Intel's design. In April, 1972, just months after releasing the 4004, Intel announced the 8008. It had 3,500 transistors and cost $650 in 2011 dollars. This 18-pin part was also constrained by the packages the company knew how to build, so it multiplexed data and addresses over the same connections. Typical development platforms were an Intellec 8 (a general-purpose 8008-based computer) connected to a TTY. One would laboriously put a tiny bootloader into memory by toggling front-panel switches. That would suck in a better loader from the TTY's 10 character-per-second paper tape reader. Then, read the editor and start typing code. Punch a source tape, read in the assembler. That read the source code in three passes before it spit out an object tape. Load the linker, again through the tape reader. Load the object tapes, and finally the linker punched a binary. It took us three days to assemble and link a program that netted 4KB of binary. Needless to say, debugging meant patching in binary instructions with only a very occasional rebuild. The world had changed. Where I worked we had been building a huge instrument that had an embedded minicomputer. The 8008 version was a tenth the price, a tenth the size, and had a market hundreds of times bigger. It wasn't long before the personal computer came out. In 1973 at least four 8008-based computers targeted to hobbyists appeared: The MCM-70, the R2E Micral, the Scelbi-8H, and the Mark-8. The latter was designed by Jon Titus, who tells me the prototype worked the first time he turned it on. The next year Radio Electronics published an article about the Mark-8, and several hundred circuit boards were sold. People were hungry for computers. "Hundreds of boards" means most of the planet's billions were still computer-free. I was struck by how much things have changed when the PC in my woodworking shop died this week. I bought a used Pentium box for $60. The seller had a garage with pallets stacked high with Dells, maybe more than all of the personal computers in the world in 1973. And why have a PC in a woodworking shop? Because we live in the country and radio stations are very weak. Instead I get stations' web broadcasts. So this story, which started with the invention of the radio several issues ago, circles back on itself. Today I use many billions of transistors to emulate a four-tube radio. By the mid-70s the history of the microprocessor becomes a mad jumble of product introductions by dozens of companies. A couple are especially notable. Intel's 8080 was a greatly improved version of the 8008. The part was immediately popular, but so were many similar processors from other vendors. The 8080, though, spawned the first really successful personal computer, the Altair 8800. This 1975 machine used a motherboard into which various cards were inserted. One was the processor and associated circuits. Others could hold memory boards, communications boards, etc. Offered in kit form for $1800 (in today's dollars), memory was optional. 1KB of RAM was $700. MITS expected to sell 800 a year but were flooded with orders for 1000 in the first month.