Olivetti Programma 101 Introduction to logic

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On this page a translation of the italian documents will be produced. As there are several people working on this, a wiki seems to be the right place to do it. After finishing a translation, we will produce a PDF of the results and publish it on the web using a Attribution-Share Alike licence as the information herein is of crucial inportance in fixing these early personal computers.

Introduction to the Logic Schematics

Olivetti  Programma  101            Legenda fogli  logici famiglia P101 

  Ivrea 6 Marzo 2010  Gaiti Giuliano 

Introduction

Due to the fact that the Logic Papers on the Olivetti Programma 101 were made in 1965 using a now complete obsolete schematic representation, an introduction to the schematic symbols used is necessary. The original seven logic sheets are redrawn on a computer to improve readability and differ only marginally from the originals.

The main component on the Printed Circuit Boards (PCBs) and in the schematic is the micromodule. It consists of a small PCB on which the components (resistors, capacitors and diodes) are arranged vertically in two rows between the small PCB and the main board. If there is a transistor used in the module, it is soldered upside down on the small PCB.

NOR

The logic function represented in the figure is a 5-input logical NOR, its inverse function creates an logical AND between the signals LA * TA * SH * KB * PO \. the result is signal VO1. The name of the signal is typically limited to two letters of the alphabet, followed by a number: • Odd number: Logical TRUE, 1 which first generator, possibly followed by 3, 5 ... • Even number: logical FALSE, 2 for the first generator, possibly followed by 4, 6 ..

Logic does not appear in the sheets, the number of legs on which are applied signals as it uses the convention of counting the signals from the top down and attribute them to the respective pins of the "micro-module P101" of Reference mounted right.

The microform NOR may be 3 or 4 rows, the transistor is mounted always in the top 2, with the reduction to 3 rows decreases the number of inputs.

The location of the micro-modules on the PCB, is shown with 5 characters, for example 01F30:

• 01 > printed circuit board • F > column • 20 > row

To improve routing of the printed circuit, micromodules can be mounted upright as in the figure, or upside down. On the schematic the mounting position of the block always indicates the top left pint of the module placed on the PCB when holding the PCB with the micromodules facing you and the edge connector down, regardless of the orientation of the modules.

In case the micro-module makes available the base of the transistor, is sacrificed an input that will always be the last among those available. In the case of NOR, open collector, does not connect the power supply collector resistance. Sheet on the open collector logic is indicated by lack of a diagonal trapezoid set the NOR.

In the case of fan-out, a requirement for driving a high number of inputs, to Because of the power loss is varied number and value of the resistor to power (+20 volt). On the sheet logical increased power is indicated by a letter P. The example shows the three variants.

The need for switching on short and controlled place by means of the selection transistors. The micro-modules that mount them are identified by the letter V.

For the logic function of the inverter, using a 3-input NOR. The two inputs superfluous may have been left flying or more likely related to Massa.

In the original sheets logical inputs flying bear no written. in sheets of computer inputs flying are indicated by the letter Z.

Flip Flop

The flip flop type is only achieved by connecting two NOR (2 micro-modules) to intersection.

The NOR used can be of different types, both for the number of inputs, availability outside of the base and fan out (normal, power or speed). The flip flop can switch either via signals applied to the inputs (resistors), both by circuits shunts connected to the base of the transistor, in slang called masks.

The figure represents a flip flop driven by both inputs that masks. The symbol of the Flip Flop is a rectangle, divided into three sections, of which:

• Left NOR whose output is the side of the True = 1 Flip Flop (Right). Door mounting the indication of the micromodule correspondent. • Central Indication of type of circuit (V, P, 2P). • Right NOR whose output is the side True = 0 of the Flip Flop (Denied). Door mounting the indication of the micromodule correspondent.

At the base of the rectangle, in bold, shows the name of the flip flop.

Extensions at the top of the rectangle representing the Flip Flop indicate: • Left Side 1. High (If any). Connects the base of transistor side September - Right of the Flip Flop to additional circuits, typically additional masks or resistance inputs. Settano the Flip Flop. 2. Low Indicates the signals applied to the elements of the NOR same. Reset the Flip Flop. • Right 1. High (If any). Connects the base of transistor side Reset - Denied the Flip Flop to additional circuits, typically masks or additional resistance inputs. Reset the Flip Flop. 2. Low Indica  i  segnali  applicati  alle  resistenze  del  NOR  lato Negato del Flip Flop. Settano il Flip Flop. 

It is noted that the signals applied to the resistors saturate the transistor, while the signals applied to the masks derivatrici act only on the falling edge interdicendolo. What effect has it that the signal applied to the resistance side left resets the flip-flop, while the signal applied to the capacitor mask, the same side, the sect. Conversely, the signals applied to the resistors right side settano the Flip Flop, while the signal applied to the capacitor mask the reset. The application of commands contemporaries and opposite, makes permanent the operation of Flip Flop.

Masks

The mask circuit is represented by a circle having, if necessary, inside a letter that specifies the type (see different types of Flip Flop). The diameter of the circle (horizontal), are drawn two segments indicating the the first signal which controls the switching of the flip flop on the capacitor and the second, the connection of the diode output to the base of the transistor. the condition signal, enable = 0, it is typically placed at the base of the circle or by a vertical segment, if the condition signal is missing, resistance is connected to ground so the mask means always enabled       Each micro-module contains two forms of the same type, identified by letters A and B.

Each of the two masks have components vertically aligned. mounted the right micromodule presents from the top diode, resistance to power, resistance and capacitor with the condition of the Mask A, on the left side. On the right side are the components of the mask B. The position 02G28, indicates that the micro-module when mounted right, will have the diode Mask A (XV1) in column G line 28 of the circuit board 02.

Buffer circuits or filter

The buffer circuit (resistance) and filter (RC) are presented as two connected vertical rectangles The left side indicates the type of circuit by a code, ZB15 for example. The right side denotates the mounting position of the micro-module on the PCB: pcb 06, column C, row 20  

 Oscillators, Monostable Circuits and Amplifiers 

Typically, these circuits are made of multiple micromodules. In the case of a monostable circuit, the number of micro-modules is 3. The top rectangle contains only the name of the circuit, in our case OP and does not represent a micromodule. The three micro-modules are represented by the next three rectangles underneath containing the installation position on the PCB. All input and output signals are shown connected to the correct micromodules and with their pin numbers.