Abstract:
PURPOSE: A security environment device and a method thereof which is independent from platform are provided to switch into security environment by turning on security bit after succeeding branch command. CONSTITUTION: A security monitor(110) watches a call of a security code by a processor(100), and creates a branch instruction. If the branch instruction is successfully operated by the processor, the security monitor makes the security bit on. If the execution of the security code is completed, the security monitor makes the security bit off. A command bypass ROM(120) receives the branch instruction from the security monitor.
Abstract:
PURPOSE: An improved look-up table compressing method, an apparatus and a method for generating a nonlinear function having a look-up table compressed using the same are provided to reduce the number of memories. CONSTITUTION: A nonlinear function generator(20) includes an analyzer(30), a memory(40) and a calculator(50). The analyzer calculates analysis information including an address from an X coordinate and outputs the analysis information. The memory includes a look-up table(41) and outputs a Y coordinate value corresponding to the address. The look-up table is stored in an address to which a plurality of Y coordinates value that are extracted at a predetermined step coordinate interval are designated. The calculator calculates an approximate value of a Y coordinate corresponding to the input X coordinate from the analysis information and the Y coordinate value.
Abstract:
A direction changing circuit of a CLV motor in an optical reproducing apparatus using a square disc which drives a motion direction of a CLV driver(5) by applying a flux control signal of a PLL circuit(1) is disclosed. In the direction changing circuit, a first operational amplifier(OP1) inverts a flux control signal of a PLL circuit(1) higher than a driving voltage. A second operational amplifier(OP2) noninverts the flux control signal of a PLL circuit(1) lower than the driving voltage. A multiplexor(7) switches outputs of the first operational amplifier(OP1) and the second operational amplifier(OP2) and applies the switched outputs to a CLV driver(5). The multiplexor(7) is switched by a switching signal of a microcomputer(4). The microcomputer(4) detects odd and even dots of a square disc.