Abstract: By embedding the EPROM2716 chip, the input and modification of user programs are realized. Keywords: ROM; PROM; EPROM; RAM; Tianhua 1 Introduction Applying economical CNC technology to upgrade old machine tools has many advantages such as low investment, quick results, and ease of implementation. Our factory, addressing the problems of low efficiency, poor accuracy, and impact on product quality and output caused by the poor performance of some old equipment, upgraded a batch of 05140 lathes using the WBQ2-003 CNC system produced by Changzhou Xiaokong Machine Tool Factory. This system comes pre-installed with 2716① (U2), 2716② (Ug) general monitoring programs and system-specific control software. The user program area U9 is reserved for user development. This paper realizes the input and modification of user programs by embedding the EPROM2716 chip. 2. Introduction to the WBQ2-003 CNC System The WBQ2-003 CNC system uses a shared 12K memory. This 12K memory is allocated as follows: SKROM consists of four 2716 chips, used to store the microcomputer monitoring program, system control program, and user program; 4K RAM consists of eight 2114 chips, with the user area located at 2000H-2F4BH. 2716① (TPBOG address 0000-07FFH) is used to store the single-board computer's general monitoring program. 2716② (PROM1 address 0800-0FFFH) is used to store the system control program. 2316③ (PROM2 address 1000-17FFH) is used for user access. This system comes with a general monitoring program and a system-specific control program when it is installed at the factory. The user program needs to be input into the RAM user area (2000～2FFFH) via the keyboard. The following describes how to solidify and modify the program in the RAM user program area. 3 EPROM writing and solidification method In addition to a +5V single board power supply, an auxiliary power supply of (+25±1)V and 30mA is also required to write to the EPROM2716. Connect this power supply to the solder joint marked +25V on the printed circuit board. (1) Irradiate the EPROM to be written with an ultraviolet lamp through the device window to erase the original contents, that is, each cell is FF. If it is a new device that has not been used, this step can be omitted. (2) With the power off, insert the EPROM2716 into the PROM2 socket. (3) Turn on the +5V and +25V power supplies. At this time, press the reset button to display the prompt "P" and turn the switch "S3↑" to the "read" position. (4) Input the content to be written into RAM (starting from 2000H) via the keyboard. (5) Press the MON key, and the LED display will show the mark "P". (6) Input 4 hexadecimal numbers, indicating the number of bytes to be written to the EPROM. Send the high bits first, then the low bits. The number of bytes = end address + 1 - start address. (7) Set the switch S3↓ to the PCM position, press the PROM and PR06 keys, the display will turn off, and the writing will begin. (8) After writing is complete, there are 3 possible results: ① The display shows the mark "P", which means that the solidification writing is correct. Retrieve the content to check if it matches the content in RAM. Turn the "S3↓" switch up and disconnect the +25V power supply. ② A 6-digit number is displayed. The first 4 digits are the address of the first erroneous cell in the EPROM, and the last 2 digits are the content in this cell. Press the NEXT key, and the monitoring program will continue to check until there are no errors, after which the display will show "P". The reason for the error is that the chip was not cleaned properly. It can be wiped clean again and solidified again. ③ If the display shows 6 numbers, 10000FF, it indicates that the +25V power supply is not connected, the polarity is reversed, or the chip is permanently damaged. The following example illustrates this. For instance, a processing program numbered YHCC is as follows: The YHCC program is burned into EPROM2 (starting from address 1000H). Byte count = end address + 1 - start address = 2014 + 1 - 2000 = 0015H. Following the above steps, proceed to step 6. When "P" is displayed, type the two bytes 0015. The burning result is shown in Figure 1. 4. Modifying the Content Burned into EPROM After the user program is burned into the EPROM, if individual contents need to be modified due to changes in processing dimensions or other reasons, the contents of the EPROM must be retrieved to the RAM user area. By programming the EPROM, data blocks (source data) stored in RAM can be transferred to any address storage unit (destination data). Alternatively, the contents of the EPROM inserted into the PROM1 or PROM2 socket can be copied into RAM. The program is as follows. Before execution, use the "MON" and "REG" keys to preset data in the E80 register, and then execute the following data block transfer instructions: EDBO……LDIR data block automatic transfer, C39C00……JPRESTAR transfer completed, return to monitoring. Example: Load the program with starting address 1000H from PROM2 (U9) into RAM with starting address 2000H. Press the "MON" key to display "P" and enter the "2900" first address. Press the "EXEC" key to execute and then display "P" and enter the "2000" first address. Press the "DISP" key to display the contents of the 2000H-2XXXH units, which are the contents of the EPROM2 from 1000H to 1XXXH. HL: source data address, the high byte is in the H register; DZ: destination data address, the high byte is in the D register; BC: total number of bytes of data transmission, the high byte is in the B register. The contents at any address can be modified in RAM. 5. Significance and effect of solidification (1) It is convenient for operators to input programs, memorize, record and modify processing dimensions. (2) A 2710 chip can be used multiple times as long as it is not permanently damaged. It is low in cost, but greatly facilitates operators and improves work efficiency and system control functions. (3) It facilitates maintenance and debugging, and avoids the phenomenon of operators not stopping the machine at noon because they are unwilling to input programs, thus extending the service life of the system. References [1] Zhou Minglei Dispersed Computer Hardware Software and Its Applications [M]. Beijing: Tsinghua University Press