SUPER MICRO Computer IRV-3702 User Manual

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I
NTERRUPT 
C
ONTROLLER
 
The IRV-3702 SBC has the equivalence of two 82C59A interrupt controllers included in the System 
Controller chip.  The controllers accept requests from peripherals, resolve priorities on pending 
interrupts and interrupts in service, interrupt the CPU, and provide the vector address of the interrupt 
service routine. The two interrupt controllers are cascaded in a fashion compatible with the IBM 
PC/AT. The interrupt priority and assignments are shown below in descending order of priority: 
 
   Highest IOCHCK/  Parity Check (Non-maskable)   
  IRQ0  System Timer (Not Available) 
  IRQ1  Keyboard (Not Available) 
  IRQ8  Real Time Clock (Not Available) 
  IRQ9  VGA Controller 
  IRQ10  Not Used 
  IRQ11  Not Used 
   IRQ12  Not Used 
  IRQ13  Co-processor (Not Available) 
  IRQ14  EIDE Disk Controller 
  IRQ15  Not Used 
  IRQ3  Serial Port 2 
  IRQ4  Serial Port 1 
  IRQ5  Alternate for Parallel Port 
  IRQ6  Floppy Disk Controller 
   Lowest IRQ7  Parallel Port 
 
  
The interrupt request lines IRQx and IOCHCK/ are available on the 98-pin edge connector except as 
noted above. 
 
T
IMERS
 
The IRV-3702 SBC has the equivalence of an 82C54 Programmable Timer included in the System 
Controller chip.  The 82C54 is a three channel Programmable Counter/Timer chip. The three timers 
are driven by a 1.19MHz clock source derived from the on-board 14.31818MHz crystal oscillator.  The 
three timers are used as follows: 
 
 TIMER Channel 0:  System Timer 
 TIMER Channel 1:  Timer for DRAM refresh 
 TIMER Channel 2:  Tone Generation for Audio 
 
C
LOCK
/C
ALENDAR AND 
CMOS RAM 
The IRV-3702 SBC includes a DS12B887 real time clock/calendar with 128 bytes of CMOS RAM and 
integral Lithium battery which provides over 10 years of data retention when the system power is off.   
 
The 128 byte CMOS RAM consists of 14 bytes used by the clock/calendar, and 114 bytes used by the 
system BIOS. 
 
K
EYBOARD 
P
ORT
 
The IRV-3702 SBC contains an IBM PC/AT compatible keyboard controller for interfacing to a generic 
IBM PC/AT compatible keyboard. The keyboard controller assembles the serial data from the 
keyboard into bytes and interrupts the CPU via IRQ1 after each byte is ready to be read.  The IRQ1 
service routine reads port 60H to get the keyboard scan code and acknowledges by sending a positive