PWM Generation

[tobias_s]

Hello, I am a student at the School of Engineering at Murdoch University, Perth, Western Australia. Currently we are using various of your 68HC11 boards. But now we have a task that requires a 50 kHz PWM signal with a resolution of duty cycle of at least 0.5 %. We are thinking of using a board with an 68HC11 K4 on it. Do you think this will work? Or do you have any other suggestions concerning PWM generation at such a frequency?
Thank you very much.
Tobias

[Harry Winter]

Hi Tobias,

Apparently, on this Web-site questions don't get answered. [It's the Web-site of the "Dead Programmers Society", from the movie with the same title.]

For a long time, I also struggled with the limits of the HC711E in speed, on chip memory and ease of ROM programming. I have now switched to the HC912B32 board from NMI. This is Motorola's answer to the performance limits of the HC11. Speed is increased by a factor of 4 to 16 and the PWM section is also improved. The Flash programming is incorporated on the NMI board and part of MaxForth 5.0L.

Motorola does not recommend the HC11 for new designs anymore and the cost for the HC12 is the same. Power consumption is also the same if you change the Xtal from 16 MHz to 4 MHz, and speed is still better! (System clock at the same 2 MHz, but all internal read/writes at 16 bits.)

Hope this is of help, Harry