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MAN/MACHINE INTERFACE FUNCTIONS
EXECUTE INTERNAL DIAGNOSTICS - 14100_222

Fire Controlman Volume 03-Digital Data Systems
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Figure  8-19.—Jumper  connections. switches except that you must physically remove and reinsert them. A jumper connector is designed for easy removal and reinsertion. They are permanent unless a configuration  change  is  required.  The  jumper connector   consists   of   a   receptacle   and   plug arrangement. The receptacle is normally mounted permanently   on   the   pcb’s   and/or   backplane/ motherboard inside the micro’s chassis. A plug (with or without a cable) makes the appropriate connection. It disables, enables, selects, and expands. Jumpers define  the  configuration  of  each  pcb,  which  will eventually  affect  operations.  Some  of  the  functions affected include mode of operation (fast or normal), clock speed, wait states, and I/O connections. Like DIP switches, jumpers are designed so you can manually position them during component installation, removal, or initial system configuration to inform the processor of  the  availability  of  the  particular  components,  as  well as the requirements of the system operators. Individual jumpers or combinations of two or three jumpers are used to specify a variety of configuration options. Battery   Protected   Storage.   —Many   newer microcomputers  have  a  hardware  setup/configuration program  stored  as  firmware.  It  has  the  capability  to display  system  configuration  data  on  the  display  screen and  to  update  system  configuration  data  via  the keyboard. The configuration data is stored in a random access  memory  (RAM)  protected  by  a  rechargeable battery so the data is retained for long time periods when the micro itself is powered down. The battery is located on the backplane/motherboard. Configuration Options. —Both DIP switches and battery  protected  storage  provide  the  same  basic configuration  data  to  the  micro. System  setup/ configuration options include the following: Date/time data (battery protected storage only) Base and expansion memory size Floppy disk drive identifiers (A, B, C or O, 1,2) Storage  capabilities  (number  of  Kbytes  of storage per drive) Hard drive data Boot drive identifier Type of video display Video refresh time period APPLY  POWER.  —Power is applied to the microcomputer with a simple ON/OFF switch usually mounted on the back of the desktop computer chassis (fig. 8-20). A separate monitor requires its own power switch. Portable micros usually have fixed time period rechargeable batteries (6, 8, or 12 hours) with a normal ac  power  option.  Presence  of  system  power  is  indicated by single indicator lamps on the front of the chassis and the monitor mounting. Sometimes in the same area as the ON/OFF switch, a selectable switch (fig. 8-20) called  a  voltage  or  line  select  switch  allows  the microcomputer to operate on voltages in the range of 100 to 130 volts or 200 to 230 volts. USE   CONTROLS,   DATA   ENTRY,   AND DATA  DISPLAY.  —Micros,  either  portable  or  desktop Figure  8-20.—Desktop  computer  back  panel. 8-17






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