Howard’s Blog

I found the neatest device a few weeks ago. It is a USB to serial adapter, _but_ it is tiny. I guess that’s why it’s called MicroUSB. It is slightly larger than a USB ‘B’ connector, and draws its power from the host.

I bought my MicroUSB from DonTronics in Austrailia and it arrived well packaged, very quickly, and with a really cute Koala bear!

The interesting thing about this adapter, and what sets it apart from regular USB to RS-232 adapters (besides the small size) is that it is at a TTL level, not +/-12V RS-232. What makes this “good” is that some development kit boards have two serial ports, and often times, only one of them has the RS-232 drivers/receivers. With this little board, you can hook up two wires (Tx and Rx) to the development kit, and then connect the USB to serial adapter straight to a PC, and use it as a COM: port.

I tried this thing under DOS (with MS-DOS Kermit 3.15) and Windows with HyperTerminal. It worked well with both.

I’m so impressed with this little guy that I may have to order several more! In fact, it’s easier to hook up than a regular RS-232 port. There are no problems with having the wrong cable, is it “null modem” or “straight” and now that many laptops don’t even have an RS-232 port, this will be a lifesaver.

-Howard

I recently bought some “identical” 64MB SD Memory cards because they were on sale at SafeWay for $9.99. When they’re selling memory cards along with groceries, you know technology has come a long way. And, for $5.00 off with my club card, I just couldn’t pass these up.

Well, first thing I wanted to do was find out how these cards are formatted, and what’s on them. I wanted to start with a clean slate, so I took one of the new cards, and filled it with zeros using WinHex.

I just can’t say enough good things about that program. It is absolutely essential for exploring raw disks and files.

Anyway, then I formatted the SD card, and took a look at it under WinHex. Just like I suspected, the Boot Sector was starting right at the front of the disk.

Then, I took out another SD card, and formatted it. This time, the card ended up with 20Kbytes less space than the first card. I though maybe the cards were slightly different cards because I bought them several weeks apart.

When I took a look at the “new” cards with WinHex, I noticed 19.5K of “Start Sectors” at the front of the card, before the DOS Boot sector even. I have no idea why they were there, but that was how the cards came, and Windows format would not use those “start sectors.” I googled “start sectors” and didn’t find anything. Then I wiped one of the new SD cards using WinHex with all 00’s. When I formatted it this time with Windows, it was 20K larger.

I’d like to know what those “Start Sectors” are for. An interesting thing about the Start Sectors is that they were all 0’s except a few bytes in what would be the boot sector. I’ll have to decode those and see what they mean. I’m guessing they mean “skip the next N sectors.”