AT89S52 Microcontroller: Application, Pinout and Datasheet
AT89S52-24JI - AT89S52 44-Pin 24MHz 8kb 8-bit Microcontroller Technical Data
AT89S52-24PC - AT89S52 40-Pin 24MHz 8kb 8-bit Microcontroller Technical Data
microcontroller - AT89S52 switched mode IO Pin 2 not setting to ground - Electrical Engineering Stack Exchange
My TechnoCare AT89S52 IC ATMEL 8051 Microcontroller Chip + 40 Pin DIP Mount IC Socket | 8 Bit Microprocessor 8Kb ISP(in System Programming) Flash Memory Up to 33MHz Clock Frequency Speed :
AT89S52-24PU Microcontroller: Diagram, Pinout, and Datasheet
Connecting the Mikroprog 8051 to a AT89S52 chip - MikroElektronika Forum
The pin representation of the AT89S52 microcontroller | Download Scientific Diagram