User`s guide

Operation Theorem  47
z RL1 & RL0 - Select Read/Load operation ( Bit 5 & Bit 4)
RL1 RL0 OPERATION
0 0 COUNTER LATCH FOR STABLE READ
0 1 READ/LOAD LSB ONLY
1 0 READ/LOAD MSB ONLY
1 1 READ/LOAD LSB FIRST, THEN MSB
z M2, M1 & M0 - Select Operating Mode ( Bit 3, Bit 2, & Bit 1)
M2 M1 M0 MODE
0 0 0 0
0 0 1 1
x 1 0 2
x 1 1 3
1 0 0 4
1 0 1 5
z BCD - Select Binary/BCD Counting ( Bit 0)
0 16-BITS BINARY COUNTER
1 BINARY CODED DECIMAL (BCD) COUNTER (4
DIGITAL)
Note The count of the binary counter is from 0 up to
65,535 and the count of the BCD counter is from 0
up to 9,999
Mode Definitions
In 8254, six operating modes can be selected. They are:
z Mode 0: Interrupt on Terminal Count
z Mode 1: Programmable One-Shot.
z Mode 2: Rate Generator.
z Mode 3: Square Wave Rate Generator.
z Mode 4: Software Triggered Strobe.
z Mode 5: Hardware Triggered Strobe.
All detailed descriptions of these modes are written in Intel's data sheet
(“http://support.intel.com/support/controllers/peripheral/231164.htm”).