© 2000 Scenix Semiconductor, Inc. All rights reserved. 59 SX User’s Manual Rev. 3.1 www.scenix.com Chapter 3 Instruction Set 3.3.6 System Control Instructions A system control instruction performs a special-purpose operation that sets the operating mode of the
device  or  reads  data  from  the  program  memory.  Included  in  this  category  are  the  following
instructions: • “bank” loads a bank number into the FSR register • “iread” reads a word from the program memory • “page” writes the page number bits in the STATUS register • “sleep” places the device in the power down mode All of these instructions take one clock cycle for execution, except in the case of the “iread” instruction
in the “turbo” device clocking mode, which takes four clock cycles. 3.4 Instruction Summary Tables Tables 3-1 through 3-6 list all of the SX instructions, organized by category. For each instruction, the table shows the instruction mnemonic (as written in assembly language), a brief description of what
the instruction does, the number of instruction cycles required for execution, the binary opcode, and
the status Bits affected by the instruction. The “Cycles” column typically shows a value of 1, which means that the overall throughput for the
instruction is one per clock cycle. In some cases, the exact number of cycles depends on the outcome
of the instruction (such as the test-and-skip instructions). The instruction execution time is derived by dividing the oscillator frequency be either one (Turbo
mode) or four (Compatible mode). The divide-by-four option is available only in the SX18/20/28AC
and SX18/20/28AC75 devices. This option is selected through the FUSE Word register The  detailed instruction descriptions in Section 3.5 fully explain the operation of  each  instruction,
including  the  Bits  affected,  the  number  of  cycles  required  for  execution,  and  usage  examples.