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• STDbus equivalent

  Keith • 04/10/2022 at 18:13 • 0 comments

  An STDbus version. Probably the design that was ported to STEbus.

• Programmable logic

  Keith • 04/08/2022 at 23:26 • 0 comments

  The STEbus writes output port bytes to an edge-triggered latch, and reads input port through an 8-bit buffer.

  The STEbus writes command bytes to an edge-triggered latch.
  

  The microcontroller writes response bytes an edge-triggered latch.

  The actions set flags to say a latch is full, and clear them when a latch is read.

  This communication through one-byte back-to-back latches is extremely simple and can easily be used for communicating with any other slave processor. There are six in the BBC Micro's Tube interface. To keep things simple, I would look at J.G. Harston's tube-through-a-single-channel software.

• Catalogue page

  Keith • 11/04/2021 at 12:34 • 0 comments

  SEMC

  The SEMC and SEMC-10 use an intelligent LSI chip set which provides all the functions required to drive a servo motor without interaction from the host computer. It has inputs for an encoder and resolver, and produces a control voltage and pulse signals to drive a servo amplifier.

  The SEMC accepts motion commands and position information over the STEbus or via an RS232 link. Commands, which may be repeating sequences, are in a simple ASCII format. The SEMC can perform a complex command sequence and interrupt the main STEbus CPU when it has finished.

  There are two limit switch inputs, 8 general-purpose TTL inputs which may optionally be used as resolver inputs and 8 general-purpose TTL outputs on the 50-way connector, which conforms to the Arcom standard signal-conditioning scheme. In addition this connector also carries the control voltage out and inputs for right and left limit switches, direction and stop/start signals. The SEMC and SEMC-10 occupy 3 I/O locations on the STEbus.

  SEMC-10 has all the features of the but has additional motion and position commands allowing complex profiles to be generated in systems.

  Power consumption:

  (from STEbus): 0.8A typical at 5V

  Features:

  • analogue and PWM control output
  • encoder or resolver feedback options
  • STEbus or RS232 communication option
  • STEbus interrupts on sequence completion
  • LEDs for debugging

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