Page 135 - Embedded Microprocessor Systems Real World Design

servo motion is implemented using the PID algorithms developed by the
Motion Control Research Group.
External Connections. Describe what the board connects to or controls:
X- and Z-axis DC servo motors and encoders, and Y-axis stepper motor.
-232 interface to system control computer.
Limit switch inputs (3).
Common emergency stop switch.
Circuit Description. This describes the circuitry and what it does: The xyz
board is implemented with an 80C188 operating at 10MHz (20MHz input).
DC motors (X- and Zaxis) are controlled by LM629 motion control ICs. The
Y-axis stepper is controlled with the timer 1 output of the 80C188. Limit
and emergency stop switches are read via an 8-bit status register. An 8-bit
command register provides discrete control bits, including stepper direction.
The RS232 interface to the system controller is implemented with a 16550
UART.
Software Interface. This is where you tell the software engineers everything
they need to know to use the board.

Mmmy:
256K flash, selected with 8OC188 UCS signal.
256K RAM, selected with 8OC188 LCS signal.
1 K EEPROM, decoded at 3000 h (h = hexadecimal).
I/O:
Address: 00
Read: Status register:
Bit 0: Emergency stop switch (1 = stop)
Bit 1: X-axis limit switch (0 = limit reached)
Bit 2: Y-axis limit switch (0 = limit reached)
Bit 3: Z-axis limit switch (0 = limit reached)
Bits 4-7: Unused
Write: Command register:
Bit 0: Y-axis stepper direction (1 = forward)
Bit 1: X-axis brake input to power driver (1 = brake on)
Bit 2: Z-axis brake input to power driver (1 = brake on)
Bits 3-7: Unused
Address 02, 03: X-axis LM629
Address 04, 05: Z-axis LM629
Address 06, 07: 16550 UART
Interrupt usage: Describe how the interrupt inputs are connected:
INTO: X-axis LM629 interrupt
INT1: Z-axis LM629 interrupt

116 Embedded Microprocessor Systems