AT89S52-24PU - 8-bit 8051 MCU, 24MHz, 8KB Flash, 40-PDIP | Microchip
Référence : AT89S52-24PU ✓ Actif| Qté | Prix unitaire | Total |
|---|---|---|
| 1 | $4.2 | $4,20 |
| 10 | $3.78 | $37,80 |
| 100 | $3.1 | $310,00 |
| 500 | $2.65 | $1 325,00 |
| 1 000 | $2.3 | $2 300,00 |
AT89S52-24PU Présentation
An 8051 microcontroller is a single-chip computer whose instruction set, register layout, and pinout are inherited from Intel's original 1970s-era MCS-51 family. In modern designs, the 8051 core sits at the entry level of the microcontroller hierarchy, occupying a lower tier of raw performance than 32-bit ARM Cortex-M parts but offering unmatched ecosystem maturity, deterministic timing, and a vast installed base of legacy code. The AT89S52 builds on this legacy by replacing the original 8051's mask ROM with 8KB of flash, allowing ISP field updates via the UART bootloader instead of an external EPROM programmer.
Key differentiating features include 1000 write/erase flash endurance cycles, fully static operation (clock can be stopped for power saving), dual data pointers for fast XRAM block moves, and a programmable hardware watchdog for unattended fault recovery. The on-chip flash relieves designers of the cost and PCB area of an external boot ROM, and the ISP interface can re-flash the device in-circuit through the serial port without removing it from the board, which simplifies field firmware updates and reduces assembly-line rework.
Architecturally, the AT89S52 uses a Harvard-style internal bus with separate program and data paths (the standard 8051 layout) and a 12-clock-per-machine-cycle core that yields one instruction every 500ns at 24MHz. The 8KB flash is mapped to the bottom of the 64KB code space, the 256-byte internal RAM occupies the lowest 256 bytes of the data space (with the upper 128-byte SFR region), and three interrupt sources are prioritized by the standard 8051 scheme. The robust 4.0V to 5.5V supply tolerance and 1000-cycle flash endurance make the device well suited to industrial-control, appliance, and hobby-embedded environments where software updates are infrequent and reliability outweighs throughput.
Typical applications include industrial motor-control boards, HVAC thermostat controllers, security-panel keypads, low-cost consumer appliances, and educational breadboard projects that benefit from the 8051's instruction-set familiarity. The through-hole PDIP-40 form factor also makes it well suited to legacy retrofits and through-hole prototyping, where a QFP package would be impractical for hand assembly or rework.
A key design consideration is the 8051 core's 12-clock-per-machine-cycle timing: at 24MHz, each instruction cycle is 500ns, which translates to roughly 1 MIPS throughput. When migrating code from higher-end 8051 derivatives (such as the AT89LP52 with 4-clock cycles), engineers must verify timing-critical ISRs, UART baud-rate tables, and timer reload values. Designers should also size the decoupling capacitor network (typically 100nF + 10uF bulk on VCC and AVCC) and configure the EA pin high for internal flash or low for external ROM.
This page synthesizes current distributor pricing, drop-in pin-compatible 8051 alternatives, and practical design notes that go beyond the manufacturer datasheet, including which AT89S52 variants retain the original AT89S52 pinout and how the AT89LP52 migration differs electrically even though the package matches.
Alternatives de remplacement direct pour AT89S52-24PU — même boîtier, compatible broche à broche. Les références à boîtier différent nécessitant une retouche du PCB sont exclues.
Outil de comparaison rapide — sélectionnez des références alternatives pour une comparaison côte à côte :
AT89S52-24JU
✅ Remplacement direct📋 Alternative de référence (hors catalogue)
AT89S52-24AU
✅ Remplacement direct📋 Alternative de référence (hors catalogue)
AT89LP52-24JU
✅ Remplacement direct📋 Alternative de référence (hors catalogue)
AT89C52-24PI
✅ Remplacement direct📋 Alternative de référence (hors catalogue)
AT89S52-24PU Valeurs maximales et caractéristiques électriques
| Core Architecture | 8051 / MCS-51 (8-bit) |
| Clock Frequency | 24 MHz |
| Program Memory | 8 KB In-System Programmable Flash |
| RAM | 256 bytes internal |
| Supply Voltage (VCC) | 4.0 V to 5.5 V |
| I/O Pins | 32 (four 8-bit ports, P0-P3) |
| Timers | Three 16-bit timer/counters |
| Communication | Full-duplex UART (1 channel) |
| Watchdog Timer | Yes (hardware, programmable) |
| Interrupt Sources | 8 (standard 8051 set) |
| Température de fonctionnement | -40 C to +85 C (industrial) |
| Boîtier | 40-pin PDIP (PDIP-40) through-hole |
| Type de montage | Through-Hole (DIP) |
| Flash Endurance | 1000 write/erase cycles |
| ROM Type | Flash |
| Statut RoHS | Compliant |
| Niveau MSL | 1 (unlimited floor life) |
Configuration des broches de AT89S52-24PU
| Broche 1 | P1.0 — Port 1 bit 0 (T2 external clock input alternate function) |
| Broche 2 | P1.1 — Port 1 bit 1 (T2EX trigger alternate function) |
| Broche 3 | P1.2 — Port 1 bit 2 |
| Broche 4 | P1.3 — Port 1 bit 3 |
| Broche 5 | P1.4 — Port 1 bit 4 |
| Broche 6 | P1.5 — Port 1 bit 5 |
| Broche 7 | P1.6 — Port 1 bit 6 |
| Broche 8 | P1.7 — Port 1 bit 7 |
| Broche 9 | RST — Reset input (active high) |
| Broche 10 | P3.0 (RXD) — Port 3 bit 0 / UART receive |
| Broche 11 | P3.1 (TXD) — Port 3 bit 1 / UART transmit |
| Broche 12 | P3.2 (INT0) — Port 3 bit 2 / External interrupt 0 |
| Broche 13 | P3.3 (INT1) — Port 3 bit 3 / External interrupt 1 |
| Broche 14 | P3.4 (T0) — Port 3 bit 4 / Timer 0 external |
| Broche 15 | P3.5 (T1) — Port 3 bit 5 / Timer 1 external |
| Broche 16 | P3.6 (WR) — Port 3 bit 6 / External data write strobe |
| Broche 17 | P3.7 (RD) — Port 3 bit 7 / External data read strobe |
| Broche 18 | XTAL2 — Crystal oscillator output |
| Broche 19 | XTAL1 — Crystal oscillator input |
| Broche 20 | GND — Ground reference (0 V) |
| Broche 21 | P2.0 — Port 2 bit 0 (A8 high address byte during external bus access) |
| Broche 22 | P2.1 — Port 2 bit 1 (A9) |
| Broche 23 | P2.2 — Port 2 bit 2 (A10) |
| Broche 24 | P2.3 — Port 2 bit 3 (A11) |
| Broche 25 | P2.4 — Port 2 bit 4 (A12) |
| Broche 26 | P2.5 — Port 2 bit 5 (A13) |
| Broche 27 | P2.6 — Port 2 bit 6 (A14) |
| Broche 28 | P2.7 — Port 2 bit 7 (A15) |
| Broche 29 | PSEN — Program Store Enable (external ROM read strobe) |
| Broche 30 | ALE — Address Latch Enable (latches P0 low address byte) |
| Broche 31 | EA — External Access Enable (low=external ROM, high=internal flash) |
| Broche 32 | P0.7 — Port 0 bit 7 (D7 data byte during external bus access; open-drain) |
| Broche 33 | P0.6 — Port 0 bit 6 (D6) |
| Broche 34 | P0.5 — Port 0 bit 5 (D5) |
| Broche 35 | P0.4 — Port 0 bit 4 (D4) |
| Broche 36 | P0.3 — Port 0 bit 3 (D3) |
| Broche 37 | P0.2 — Port 0 bit 2 (D2) |
| Broche 38 | P0.1 — Port 0 bit 1 (D1) |
| Broche 39 | P0.0 — Port 0 bit 0 (D0) |
| Broche 40 | VCC — Positive power supply (4.0 V to 5.5 V) |
Applications typiques
AT89S52-24PU convient pour 6 applications: Industrial Motor Control Board, HVAC Thermostat Controller, Security Panel Keypad Controller, Educational Microcontroller Trainer, Home Appliance Control Board, Legacy 8051 Retrofit Project.
Industrial Motor Control Board
The AT89S52-24PU's deterministic 8051 timing, 24 MHz clock and 32 I/O lines map neatly onto brushed-DC and small stepper motor drivers common in industrial lines. The three 16-bit timers (T0, T1, T2) generate the PWM channels for both speed and current control, while the hardware watchdog catches runaway firmware in unmanned panels. With 8 KB of ISP flash, field technicians can update commutation tables over the UART bootloader without removing the controller from its housing, and the 4.0-5.5 V window tolerates the typical 5 V industrial backplane. Unlike an ARM Cortex-M0 alternative, the 8051 cycle timing allows the engineer to compute exact loop counts for each PWM period.
Recommandé
HVAC Thermostat Controller
Wall-mounted thermostats and zone controllers lean on the AT89S52-24PU because the 8051 instruction set and tiny footprint keep BOM cost well under competing ARM parts. The UART drives the LCD display and Modbus link to the air-handler, while the ISP flash lets installers push seasonal firmware without dismounting the unit. With 256 bytes of RAM and three timers, the part handles temperature sampling, hysteresis scheduling, and relay de-bounce in a single chip; the watchdog automatically resets the controller if firmware hangs in relay-update loops. The -40 C to +85 C industrial temperature window suits unconditioned utility closets, and the 4.0-5.5 V supply aligns with the standard 5 V regulated rail off a 24 VAC wall transformer.
Recommandé
Security Panel Keypad Controller
Intrusion alarm panels value the AT89S52-24PU for its predictable 8051 interrupt response and ruggedized ISP update path. The 32 I/O pins drive a 4x4 keypad matrix, the LCD or seven-segment display, siren drivers, and zone-input sensors, while the hardware watchdog guards against firmware lockups that would otherwise defeat the alarm. Engineered in 8 KB of flash, the panel can encrypt and store hundreds of user PINs and event logs, and the ISP link lets installers push security patches. The full-duplex UART feeds the central monitoring station over a phone-line modem or IP link, and the industrial temp range of -40 C to +85 C suits garage and attic installations where temperature swings are wide.
Recommandé
Educational Microcontroller Trainer
University freshman labs and maker kits rely on the AT89S52-24PU because the through-hole PDIP-40 fits standard 40-pin IC sockets and breadboards, allowing students to mount and swap parts by hand without reflow equipment. The standard 8051 instruction set is taught in nearly every embedded-computing textbook, and 8 KB of flash is more than enough for coursework on timers, interrupts, the UART, and watchdog programming. The ISP bootloader also teaches in-circuit programming over a USB-to-UART cable, while the 5 V supply matches breadboard rails. Compared to surface-mount ARM parts, the AT89S52-24PU is large enough to probe with an oscilloscope ground clip and clearly labeled with each pin's function, and that visibility dramatically speeds up teaching loops.
Recommandé
Home Appliance Control Board
Washing-machine, dishwasher, and microwave control boards remain a stronghold for the AT89S52-24PU because the 8051's deterministic 1 MIPS throughput keeps costs low while handling the real-time tasks of cycle sensing, motor timing, and user-interface scanning. Engineers program the cycle sequence and safety interlocks in 8 KB of ISP flash and field-update the firmware over the UART bootloader to roll out bug fixes. The watchdog timer resets the board if the controller stalls in a long motor-start loop, and the 32 I/O lines drive the keypad, buzzer, triac-controlled loads, and EEPROM for cycle counters. The 4.0-5.5 V supply pairs with the rectified 24 V mains transformer that powers most appliances, and the industrial temperature range covers the hot, enclosed control-box environment.
Recommandé
Legacy 8051 Retrofit Project
Many 1990s-era industrial machines and consumer appliances still rely on aging 8051 mask-ROM parts now in obsolescence. The AT89S52-24PU serves as a faithful pin-compatible retrofit because it preserves the original 8-bit core, 8051 register set, and 40-pin PDIP pinout while adding 8 KB of ISP flash for code modernization. Engineers can replicate the original timing-critical ISRs on the 12-clock core without rework, and the In-System Programming avoids desoldering the controller from the board. With 256 bytes of RAM, three timers, and a hardware watchdog, this is a true like-for-like part. The 24 MHz speed grade matches the legacy AT89C52 timing such that existing firmware drops in unmodified, while the ISP features provide a future path for security patches and feature upgrades.
Recommandé
Récapitulatif des produits recommandés
Données de référence d'ingénierie pour AT89S52-24PU — comparaison, recommandations de conception et informations de conformité.
Guide de sélection
Comparaison avec les alternatives
| Paramètre | Ce produit | AT89S52-24JU | AT89S52-24AU | AT89LP52-24JU | AT89C52-24PI |
|---|---|---|---|---|---|
| Package | PDIP-40 | PLCC-44 | TQFP-44 | PLCC-44 | PDIP-40 |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Clock Frequency | 24 MHz | 24 MHz | 24 MHz | 24 MHz (1x cycle) | 24 MHz |
| Flash Memory | 8 KB ISP Flash | 8 KB ISP Flash | 8 KB ISP Flash | 8 KB ISP Flash | 8 KB (no ISP) |
| RAM | 256 bytes | 256 bytes | 256 bytes | 256 bytes | 256 bytes |
| Watchdog Timer | Yes (hardware) | Yes (hardware) | Yes (hardware) | Yes (hardware) | No |
| ISP Bootloader | Yes (UART) | Yes (UART) | Yes (UART) | Yes (UART, faster) | No (parallel programmer) |
| Operating Temperature | -40 C to +85 C | -40 C to +85 C | -40 C to +85 C | -40 C to +85 C | -40 C to +85 C |
Principaux différenciateurs
- Industrial temperature range and through-hole PDIP (vs AT89S52-24PI (legacy))
- True 8051 12-clock-per-cycle timing preserved (vs AT89LP52-24JU)
- In-System Programming over UART (vs AT89C52-24PI)
Notes de conception
Place a 100 nF decoupling capacitor directly across VCC (pin 40) and GND (pin 20) within 5 mm of each pin to suppress switching transients. Add a 10 uF bulk capacitor at the regulator output. The AT89S52-24PU datasheet specifies a maximum 5.5 V supply; operation above this level will damage the device and may corrupt flash cells during write cycles.
When using a quartz crystal with XTAL1 (pin 19) and XTAL2 (pin 18), keep traces short and symmetric to ground and avoid routing high-frequency signals across the crystal network. Place load capacitors (typically 22-33 pF for HC-49 crystals at 24 MHz) close to the pins. The AT89S52 has internal oscillation buffers but cannot tolerate stray capacitance from long traces, which may shift the actual oscillator frequency and disturb UART baud-rate accuracy.
When migrating from AT89S52 to AT89LP52 (faster 1x core), two board-level changes are required per Microchip application note doc3718: tie the RST pin POL high, and verify the EA pin polarity matches the desired boot source. Also re-compute all UART baud-rate divisors and timer reload values since the per-instruction timing is 12x faster at the same nominal 24 MHz.
Informations de conformité
RoHS compliant per Microchip product page and DigiKey. Not AEC-Q100 qualified (industrial-grade -40 C to +85 C). Lead-free and halogen-free per -PU ordering code.
