Features Compatible with MCS -51 Products 8K Bytes of In-System Programmable (ISP) Flash Memory Endurance: 10,000 Write/Erase Cycles 4.0V to 5.5V Operating Range Fully Static Operation: 0 Hz to 33 MHz Three-level Program Memory Lock 256 x 8-bit Internal RAM 32 Programmable I/O Lines 8-bit Three 16-bit Timer/Counters Eight Interrupt Sources Microcontroller Full Duplex UART Serial Channel Low-power Idle and Power-down Modes with 8K Bytes Interrupt Recovery from Power-down Mode Watchdog Timer In-System Dual Data Pointer Power-off Flag Programmable Fast Programming Time Flexible ISP Programming (Byte and Page Mode) Flash Green (Pb/Halide-free) Packaging Option AT89S52 1. Description The AT89S52 is a low-power, high-performance CMOS 8-bit microcontroller with 8K bytes of in-system programmable Flash memory. The device is manufactured using Atmels high-density nonvolatile memory technology and is compatible with the indus- try-standard 80C51 instruction set and pinout. The on-chip Flash allows the program memory to be reprogrammed in-system or by a conventional nonvolatile memory pro- grammer. By combining a versatile 8-bit CPU with in-system programmable Flash on a monolithic chip, the Atmel AT89S52 is a powerful microcontroller which provides a highly-flexible and cost-effective solution to many embedded control applications. The AT89S52 provides the following standard features: 8K bytes of Flash, 256 bytes of RAM, 32 I/O lines, Watchdog timer, two data pointers, three 16-bit timer/counters, a six-vector two-level interrupt architecture, a full duplex serial port, on-chip oscillator, and clock circuitry. In addition, the AT89S52 is designed with static logic for operation down to zero frequency and supports two software selectable power saving modes. The Idle Mode stops the CPU while allowing the RAM, timer/counters, serial port, and interrupt system to continue functioning. The Power-down mode saves the RAM con- tents but freezes the oscillator, disabling all other chip functions until the next interrupt or hardware reset. 1919DMICRO6/082. Pin Configurations 2.3 44-lead PLCC 2.1 40-lead PDIP (T2) P1.0 1 40 VCC (T2 EX) P1.1 2 39 P0.0 (AD0) P1.2 3 38 P0.1 (AD1) P1.3 4 37 P0.2 (AD2) (MOSI) P1.5 7 39 P0.4 (AD4) P1.4 5 36 P0.3 (AD3) (MISO) P1.6 8 38 P0.5 (AD5) (MOSI) P1.5 6 35 P0.4 (AD4) (SCK) P1.7 9 37 P0.6 (AD6) (MISO) P1.6 7 34 P0.5 (AD5) RST 10 36 P0.7 (AD7) (SCK) P1.7 8 33 P0.6 (AD6) (RXD) P3.0 11 35 EA/VPP RST 9 32 P0.7 (AD7) NC 12 34 NC (RXD) P3.0 10 31 EA/VPP (TXD) P3.1 13 33 ALE/PROG (TXD) P3.1 11 30 ALE/PROG (INT0) P3.2 14 32 PSEN (INT0) P3.2 12 29 PSEN (INT1) P3.3 15 31 P2.7 (A15) (INT1) P3.3 13 28 P2.7 (A15) (T0) P3.4 16 30 P2.6 (A14) (T0) P3.4 14 27 P2.6 (A14) (T1) P3.5 17 29 P2.5 (A13) (T1) P3.5 15 26 P2.5 (A13) (WR) P3.6 16 25 P2.4 (A12) (RD) P3.7 17 24 P2.3 (A11) XTAL2 18 23 P2.2 (A10) XTAL1 19 22 P2.1 (A9) GND 20 21 P2.0 (A8) 2.2 44-lead TQFP (MOSI) P1.5 1 33 P0.4 (AD4) (MISO) P1.6 2 32 P0.5 (AD5) (SCK) P1.7 3 31 P0.6 (AD6) RST 4 30 P0.7 (AD7) (RXD) P3.0 5 29 EA/VPP NC 6 28 NC (TXD) P3.1 7 27 ALE/PROG (INT0) P3.2 8 26 PSEN (INT1) P3.3 9 25 P2.7 (A15) (T0) P3.4 10 24 P2.6 (A14) (T1) P3.5 11 23 P2.5 (A13) 2 AT89S52 1919DMICRO6/08 (WR) P3.6 12 44 P1.4 (RD) P3.7 13 43 P1.3 XTAL2 14 42 P1.2 XTAL1 15 41 P1.1 (T2 EX) GND 16 40 P1.0 (T2) GND 17 39 NC (A8) P2.0 18 38 VCC (A9) P2.1 19 37 P0.0 (AD0) (A10) P2.2 20 36 P0.1 (AD1) (A11) P2.3 21 35 P0.2 (AD2) (A12) P2.4 22 34 P0.3 (AD3) (WR) P3.6 18 6 P1.4 (RD) P3.7 19 5 P1.3 XTAL2 20 4 P1.2 XTAL1 21 3 P1.1 (T2 EX) GND 22 2 P1.0 (T2) NC 23 1 NC (A8) P2.0 24 44 VCC (A9) P2.1 25 43 P0.0 (AD0) (A10) P2.2 26 42 P0.1 (AD1) (A11) P2.3 27 41 P0.2 (AD2) (A12) P2.4 28 40 P0.3 (AD3)