STC89C52RC-40I-PDIP40 ,6T or 12T per machine cycle

STC89xx series, which is produced by STC MCU Limited, is a 8-bit single-chip microcontroller with a fully compatible instruction set with industrial-standard 80C51 series microcontroller. There is 64K bytes flash memory embeded for appliaction program, which is shared with In-System-Programming code.In-SystemProgramming (ISP) and In-Application-Programming (IAP) support the users to upgrade the program and data in system. ISP allows the user to download new code without removing the microcontroller from the actual end product;IAP means that the device can write non-valatile data in Flash memory while the application program is running. There are 1280 bytes or 512 bytes on-chip RAM embedded that provides requirement from wide field application. The user can configure the device to run in 12 clocks per machine cycle, and to get the same performance just as he uses another standard 80C51 device that is provided by other vendor, or 6 clocks per machine cycle to achieve twice performance. The STC89xx series retain all features of the standard 80C51. In addition, the STC89xx series have a extra I/O port (P4 ), Timer 2, a 8-sources, 4-priority-level interrupt structure, on-chip crystal oscillator,and a one-time enabled Watchdog Timer.

link
https://www.stcmicro.com/datasheet/STC89C51RC-en.pdf

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