Everything's packaged in a zip file.
I use Ivex's CAD tools. See their
homepage for the tools.
I converted the pages to jpegs so you can get a feel for the design.
You will want to download the zip files to get the real things.
PIC, latches: page 1
Power, RS232 Driver, Misc: page 2
H Bridges: page 3
Palm Basic Software:
I use my Palm 3xe as a paddle to control the mount. The software for the
Palm is written in
Hot Paw Basic.
The screen is formatted with 4 buttons. When the buttons are pressed the
program sends commands via the serial line to the mount. I use a standard
Palm serial cable. The Basic program
is in the distribution. Any computer that can communicate over a serial
line at 9600 baud could be used to control the steppers. This works OK
but tends to burn through batteries pretty quickly since it takes lots
of power to run the serial line and the Palm's back light.
Timer 0 is used as a free running clock, clocked at 1MHZ. The prescaler is set to 256 so that the timer rolls over every 65.536 MS or a little more than 15 times per second. It is used for gross user level timing of events such as polling the battery value.
Command set
F[m][dir] [count] | Full step [count] steps |
GC | Gets the count for both axes |
GB | Gets the battery voltage |
M[m][dir] | Starts an axis slewing |
Q[m] | Stop |
I[m] | Idle: Quit and turn power off |
R | Reset |
SC[m] [count] | Sets the saved count for an axis |
SS[speed] | Sets speed for next Slew command (both axes) |
T | Starts RA tracking |
U[m][dir] [count] | Microstep [count] steps |
Abbreviations:
[count] - signed 32 bit count of full steps |
[m] can be "R" or "D" and specifies which motor to use |
[speed] is "T" for Tracking speed |
"G" for Guide speed |
"L" for Lunar speed |
"S" for Solar speed |
"M" for Medium (8x) speed |
"F" for Fast (32x) speed |
[dir] is "+" or "-" |