It is in accordance with some special procedures and processes of greenlaser pointer

Based on superior performance, easy to download, and inexpensive, we selected microcontroller AT89S52. Figure 3.1 3.2.1 AT89S52 is the overall control circuit composition of the CPU the AT89S52 CPU processing 8-bit binary number or code. The microcontroller core components, the CPU contains the CPU inside the arithmetic unit, the controller, as well as a number of registers, etc. parts to. (1) internal data memory (RAM): AT89S52 microcontroller chip 256 RAM units, of which 128 units dedicated registers occupy only the first 128 units can be used as a register for a user, used to store read and write data.  green laser pointer  has the double energy-saving control.
Commonly referred to as internal data memory refers to the first 128 units, referred to the internal RAM. Address the range of 00H to FFH (256B) is a multi-purpose multi-purpose data memory. Data storage, general purpose working registers, stack, bit address space. ⑵ internal program memory (ROM): The AT89S52 is within 4KB/8KB bytes of ROM (51 Series 4KB, the 51 series to 8KB) for stored procedures, raw data or tables. Therefore called procedural memory, referred to the internal RAM. Address range 0000H ~ FFFFH (64KB). ⑶ timer / counter AT89S52 2 16-bit timer / counter (52 series of three 16-bit timer / counter).  green laser pointer  is user-friendly.
In order to achieve the timing or counting functions, and its timing or counting the results of the computer control. Timing rely on the frequency of some clock frequency count to achieve, to do the counter, P3.4 (T0) or the P3.5 (T1) port of the low pulse count. ⑷ parallel I / O port AT89S52 a total of four 8-bit I / O port (P0, P1, P2, and P3) data input and output. ⑸ serial port the 6 AT89S52 is a programmable full-duplex serial port to the serial data transfer between the microcontroller and other devices. The serial port functions, either as full-duplex asynchronous communication transceivers can also be use as a shifter. RXD (P3.0) pin for receiving port, the TXD (P3.1) pin for the send port. This function of green laser pointer is optional.
Interrupt Control system: AT89S52 microcontroller interrupt function, in order to meet the needs of the different control applications. 51 series of five interrupt sources (52 Series 6 interrupt sources), external interrupt 2, two timer interrupt, a serial interrupt, all interrupts are divided into senior and junior two priority levels. ⑺ timing and control unit: AT89S52 microcontroller internal high-gain inverting amplifier based input XTAL1 output XTAL2 are. MCS-51 chip's internal clock circuit, an external quartz crystal tuning capacitor. The clock circuit generates a clock pulse sequence for a microcontroller. 3.2.2 AT89S52 is the bus structure AT89S52 pin except the power, reset, clock access.  green laser pointer  has the laser indicators.
User I / O port part of the P3, and the remaining pins are set to achieve system expansion. These pins constitute a form of a three bus, namely: (1) the address bus (AB): The address bus width is 16, therefore, the periphery of the direct address of the external memory is 64K bytes. 16-bit address bus address latch the lower 8 address (A0 ~ A7); from P0 through P2 port directly provide high eight address (A8 to A15). (2) data bus (DB): the data bus width of 8, by the P0 port. (3) control bus CB): by the second part of the P3 port functional status, and four independent control lines the RESET, RESET the EA, the ALE the PSE composition.  green laser    has the plug and play characteristics.