CompuServe Messages

The 68HC11 isn't too bad of a chip. I get to do some real assembler programming! Am starting to learn about all those memory addressing modes I ran away from on the 680×0. My biggest problem is trying to remember what resources are available on the HC11. Then decided to stick to the ones I need and ignore the rest. Brilliant, huh! Using the 68HC11A1P, one of the originals, but it does the job. The board it comes on (designed by a member of TAPR (Tucson Amateur Packet Radio Corporation)) is designed to act as a deviation meter, once interfaced to a receiver. It is used in Expanded mode, comes with a 32k EPROM, room for 32k RAM, synthesizer chip, VCO circuitry, op-amp, serial-parallel shifter, and LED display driver, PAL for chip select, and a TC232 RS-232 driver. The kit of parts goes for about US$99. This configuration doesn't leave much in the line of discrete i/o available, but is enough for the original application, and the application I am putting another one of these units to use for. This other one still uses the synthesizer chip, but use an external VCO – part of the receiver chip circuitry on another board. The serial-parallel shifter was used to hold the pattern for the LED display, and used a couple of transistors to select which digit to turn on. I have this connected to a 2 line by 40 character LCD display instead. Took me two days to get the software working (stupid mistake!) to drive the display. Since I can't read back form the display, have to use delay loops to give the display enough time to digest anything sent to it. All four A/D channels are in use, just as in the original Deviation Meter design. One channel monitors the VCO tuning voltage (don't do anything with this except display it), one channel watches the Received Signal Strength, and the last two channels what the + and – peaks of the discriminator output. I will eventually use these two channels to track the incoming signal to follow the doppler shift of the satellite's signal. Right now I have a performance problem to work out with the current setup for the satellites. Might have to get a new modem/TNC (Terminal Node Controller) for the satellite stuff. Should know what I am going to do by the end of the weekend. Would have been nice if this board used one of the newer version of the 'HC11 that offered two more ports. Then I could waste time trying to interface to the graphical LCD displays. Just received the Winter/94 issue of Motorola's "Update" rag (BR128/D). Motorola now has a available a number of libraries for downloading into the TPU (Time Processing Units) on the 68332 and 68HC16 to give them new functions. They have added functions like "Multi-phase Motor Commutation (COMM)", "Hall Effect Decode (HALLD)", and a couple of new Stepper Motor functions. Bunch of others, too. These can be downloaded from their MCU BBS (512-891-3733). There are printed application notes avaialable for these functions. Looks like time to order more App Notes. Well, it is -32C outside. Snowmobiling is out of the question, so I get to spend the day playing in the shack, and see if I can make some headway on my poor thru-put on the birds. 73, Kelly