-----Review of Atmel FLASH Microcontrollers and the ATM52 programmer By Roger Arrick, roger@robotics.com Atmel (www.atmel.com), the maker of Flash-style memory chips has used their expertise to create 8051-style microcontroller chips with on-board Flash program memory instead of the typical EPROM type. On the surface this doesn't sound like a big deal but if you've ever developed a microcontroller project without an emulator, you know it takes endless cycles of program, burn, test, UV erase.... The longest phase of this process is the UV erase which typically takes 20-30 minuites. Because it takes that long, you end up needing to have about 10 chips so you can be working while chips are erasing. In general, erasing is a headache. UV erasing requires that the chip have a window. OTP (one time programmable) versions of microcontroller chips are exactly the same as their EPROM brothers but simply don't have the window and therefore can't be erased. Why leave off the window you ask? Well, cost. That little window adds several dollars to the cost of the part, sometimes much more. Since the Atmel flash microcontrollers don't require UV erase, you don't need the window, and guess what, they're cheaper. Another guess what, you don't need to UV erase, simply stick it in your programmer and select erase. This normally takes a few seconds. What's the downside you say? Well, the flash parts can't be programmed with the same programmer/programming module as standard 8051 parts. Most programmers like the Needham EMP20 ($450) already come with a module for the Atmel parts. Others may require a custom module or even new software. The cheap programmer I had (~$100) couldn't even do this part with new software so I had to get the more expensive EMP20. Atmel currently offers a handful of versions of Flash 8051 micros. Here's a partial list: AT89S51 80C51 with 4k flash, 128 bytes ram, 2 timers, 40 pin package. AT89S52 80C52 with 8k flash, 256 bytes ram, 3 timers, 40 pin package. AT89S1051 1k flash, 64 bytes ram, 20 pin package, 1 timer, No UART. AT89S2051 2k flash, 128 bytes ram, 2 timers, 20 pin package. There are others, request an Atmel databook for more information. The 20 pin parts will give any PIC micro a serious run for it's money. You can use standard 8051 programming development tools. But, you do need to have a programmer that can program the special parts. At the time I began using Atmel parts, the Needham EMP20 looked like the best bargin for a programmer but it still cost $450. The Needham products are top-notch and not nearly as expensive as some of the other options. Their software has a huge array of supported parts. The package comes with several personality modules for different types of parts. A very well made product for sure. Now there's several on the market that are lower-end and would be affordable to a tinkerer and made specifically for the Atmel microcontrollers. After looking around and comparing features I selected the ATM52 by MITE, a CZ company. You can find them on the web at www.mite.anet.cz. The ATM52 is designed to program the Atmel 89S51,52,2051, and 1052 only, no EPROM or standard 8051 parts can be done. This was fine for my requirements and the unit only costs about $100.00. They sent me an order form via fax and I filled it out with a credit card #. I'm not too excited about giving my card # of the net just yet. Give it time though. The shipping charges were a whopping $30.00 but overall this seemed like a fair deal. After about 2 weeks the unit arrived in a small cardboard box. The box contained an AC adapter, 3.5" PC diskette, serial port cable, and the board itself. The board contains a 40 pin high-quality ZIF socket, is about 4" x 5" and has 4 rubber feet on the bottom. The first thing I noticed was the fact that the AC adapter was a strange (to me anyway) 220v European model with 2 round prongs instead of what we have here in the states. Since the voltage was 12VDC, I just found one I had and used it instead. The European model went into my junk pile to be used for future projects. The next thing I noticed was NO MANUAL. At first I thought it was missing, but now I realize that this thing is so easy to use, no manual is needed. I simply created a directory on the HD and copied the 2 files from the floppy into it. On my Windose 95 desktop, I clicked the right mouse button while pointing at an open folder, selected NEW, found the .exe file, and placed it into the folder. No problem. Clicking the ICON causes the DOS program to pop up where there are several pull down menus and a memory display. The first thing that happened was, well, nothing, then a message appeared saying that communications could not be established. After double checking the serial cable and com port #, I noticed that the power light on the board was off. After much head scratching, I noticed that the adapter needed to have the center pin minus and the outside ring positive, the exact opposite of what I expected. I clipped my AC adapter's wires and switched them. Plugged the connector back in and everything worked just fine. MITE had placed a blocking diode to protect the board in the event of such a screw-up - good going guys! Remember it costs $30 to ship this thing. Using the software is so self-expanitory there's no need to go into it here. A small but useful on-line help file is available to answer all but the dumbest questions. All in all, I like what I got for my money and would recommend it to others tinkering around with micros. There's not too many products which cause me to realize an important lesson of life but this one did - I've got 4 power strips on my workbench and that's not enough!!!