ATMEGA161L-4AC - 16KB Flash 4MHz AVR MCU 44-TQFP | Microchip
MPN: ATMEGA161L-4AC ✗ סוף ייצורATMEGA161L-4AC סקירה
An 8-bit microcontroller is a complete computing system on a single chip, combining a processor core, program memory, data memory, timers, and serial communication peripherals into one package. Within the embedded hierarchy, the AVR ATmega family sits under Microchip's (formerly Atmel's) microcontroller product line, which itself belongs to the broader categories of MCU, integrated circuit, and semiconductor.
Key features include the Advanced RISC architecture executing 130 powerful instructions, most in a single clock cycle; 32 general-purpose working registers; three flexible Timer/Counters with compare modes; a real-time counter; and a programmable Watchdog Timer with an internal oscillator.
Technically, the ATmega161 integrates two programmable serial UARTs - a distinguishing feature for its class - plus an SPI serial interface and internal and external interrupt sources. The external oscillator type supports precise clocking, and the device supports In-System Programming and Self-programming of Flash for field updates. External memory expansion is supported through an address/data bus interface.
Typical applications include legacy industrial control systems, dual-UART communication gateways, appliance control boards, and maintenance/repair of existing ATmega161-based equipment.
Design consideration: since the ATmega161 family is discontinued, new designs should target its pin-compatible successor ATmega162, while repair programs can fall back on this L-grade 4MHz variant for low-voltage systems.
This page synthesizes distributor availability, drop-in alternatives, pricing history, and practical design notes not found in the manufacturer datasheet.
חלופות תחליף ישיר עבור ATMEGA161L-4AC — אותו מארז, תואם פין-לפין. חלקים במארז שונה הדורשים עיבוד מחדש של ה-PCB אינם נכללים.
וריאנטים בסדרה זו
דגמים מאותה סדרה התואמים Drop-in עם ATMEGA161L-4AC (אותו גורם צורה וטביעת רגל) — שונים ב Supply Voltage Range, Flash Memory, Instruction Set, Package, Mounting Type.
ATMEGA161L-4PI
✅ Drop-Inצור קשר לקבלת מחיר
הצג גיליון נתונים ←ATMEGA161-4AC
✅ Drop-In ⚠️ מפרטים לא מאומתים📋 חלופה להתייחסות (לא בקטלוג)
ATMEGA162-16AU
✅ Drop-In ⚠️ מפרטים לא מאומתיםצור קשר לקבלת מחיר
הצג גיליון נתונים ←ATMEGA16-16AU
✅ Drop-In ⚠️ מפרטים לא מאומתיםצור קשר לקבלת מחיר
הצג גיליון נתונים ←ATMEGA128-16AU
✅ Drop-In ⚠️ מפרטים לא מאומתיםצור קשר לקבלת מחיר
הצג גיליון נתונים ←ATMEGA161L-4AC דירוגים מרביים ומאפיינים חשמליים
| Core Processor | AVR 8-bit |
| Core Size | 8-bit |
| Speed | 4 MHz |
| Program Memory Size | 16 KB (8K x 16) FLASH |
| Program Memory Type | FLASH (In-System or Self-programmable) |
| RAM Size | 1 KB (1K x 8) SRAM |
| EEPROM Size | 512 bytes |
| Number of I/O | 35 |
| Working Registers | 32 general purpose |
| Instruction Set | 130 powerful instructions, most single-cycle |
| Connectivity | SPI, 2x UART/USART |
| Peripherals | 3x Timer/Counter with Compare, WDT, Real-time Counter |
| Oscillator Type | External |
| מארז / Case | 44-TQFP (10x10 mm) |
| סוג הרכבה | Surface Mount |
| Packaging | Tray |
תצורת פינים של ATMEGA161L-4AC
| פין 1 | PB0/SS — Port B bit 0 / SPI Slave Select |
| פין 2 | PB1/T1 — Port B bit 1 / Timer1 external clock input |
| פין 3 | PB2/AIN0 — Port B bit 2 / Analog Comparator input 0 |
| פין 4 | PB3/AIN1 — Port B bit 3 / Analog Comparator input 1 |
| פין 5 | PB4/OC0 — Port B bit 4 / Timer0 Output Compare |
| פין 6 | PB5/SCK — Port B bit 5 / SPI Serial Clock |
| פין 7 | PB6/MISO — Port B bit 6 / SPI Master In Slave Out |
| פין 8 | PB7/MOSI — Port B bit 7 / SPI Master Out Slave In |
| פין 9 | RESET — Active-low reset input |
| פין 10 | VCC — Digital supply voltage |
| פין 11 | GND — Ground |
| פין 12 | XTAL1 — External oscillator input |
| פין 13 | XTAL2 — External oscillator output |
| פין 14 | PD0/RXD0 — Port D bit 0 / UART0 receive |
| פין 15 | PD1/TXD0 — Port D bit 1 / UART0 transmit |
| פין 16 | PD2/RXD1 — Port D bit 2 / UART1 receive |
| פין 17 | PD3/TXD1 — Port D bit 3 / UART1 transmit |
| פין 18 | PD4/INT0 — Port D bit 4 / External interrupt 0 |
| פין 19 | PD5/INT1 — Port D bit 5 / External interrupt 1 |
| פין 20 | PD6/ICP1 — Port D bit 6 / Timer1 Input Capture |
| פין 21 | PD7/OC2 — Port D bit 7 / Timer2 Output Compare |
| פין 22 | PC0 — Port C bit 0 / general purpose I/O |
| פין 23 | PC1 — Port C bit 1 / general purpose I/O |
| פין 24 | PC2 — Port C bit 2 / general purpose I/O |
| פין 25 | PC3 — Port C bit 3 / general purpose I/O |
| פין 26 | PC4 — Port C bit 4 / general purpose I/O |
| פין 27 | PC5 — Port C bit 5 / general purpose I/O |
| פין 28 | PC6 — Port C bit 6 / general purpose I/O |
| פין 29 | PC7/TOSC2 — Port C bit 7 / RTC oscillator output |
| פין 30 | PC8/TOSC1 — RTC oscillator input pin (TOSC1) |
| פין 31 | PA7 — Port A bit 7 / address/data bus (external memory) |
| פין 32 | PA6 — Port A bit 6 / address/data bus (external memory) |
| פין 33 | PA5 — Port A bit 5 / address/data bus (external memory) |
| פין 34 | PA4 — Port A bit 4 / address/data bus (external memory) |
| פין 35 | PA3 — Port A bit 3 / address/data bus (external memory) |
| פין 36 | PA2 — Port A bit 2 / address/data bus (external memory) |
| פין 37 | PA1 — Port A bit 1 / address/data bus (external memory) |
| פין 38 | PA0 — Port A bit 0 / address/data bus (external memory) |
| פין 39 | VCC — Digital supply voltage |
| פין 40 | GND — Ground |
| פין 41 | PE0/ALE — Port E bit 0 / External memory Address Latch Enable |
| פין 42 | PE1/OC1B — Port E bit 1 / Timer1 Output Compare B |
| פין 43 | PE2/OC1A — Port E bit 2 / Timer1 Output Compare A |
| פין 44 | WR/RD — External memory write/read strobes |
יישומים טיפוסיים
ATMEGA161L-4AC מתאים עבור 6 יישוםs: Legacy Industrial Control Systems, Dual-UART Communication Gateways, SPI Peripheral Expansion and Monitoring, Appliance and Consumer Equipment Control, Battery-Powered Low-Voltage Instruments, External-Memory Expandable Data Loggers.
Legacy Industrial Control Systems
The ATMEGA161L-4AC fits legacy industrial control boards originally designed around the ATmega161 because it is the exact silicon that these controllers were qualified with. Its 16KB Flash holds ladder-style or state-machine control firmware, while 1KB SRAM and 512B EEPROM retain setpoints and counters across power cycles. The 35 I/O lines directly drive relays, contactors, and indicator stacks through the three Timer/Counters with compare modes for deterministic PWM and timing. In repair and sustaining programs, swapping a failed device with the identical 4MHz L-grade part avoids any requalification: no firmware changes, no crystal retuning, and identical electrical behavior on 24V industrial panel boards. Supply from broker stock is the trade-off, so maintenance planners should buy spares in batches while stock persists.
מומלץ
Dual-UART Communication Gateways
The distinguishing feature of the ATMEGA161L-4AC for protocol conversion work is its pair of programmable serial UARTs, rare in 8-pin-count AVRs of its generation. A gateway can simultaneously listen on an RS-485 field bus on UART0 and stream to an RS-232 service port on UART1, buffering messages in the 1KB SRAM. At 4MHz, the AVR core sustains baud rates up to 38.4 kbps on both ports concurrently with headroom for framing and CRC checks in the 130-instruction single-cycle RISC core. The external oscillator ensures the baud-rate generator accuracy needed for multi-drop buses, and the Watchdog Timer with internal oscillator recovers the link after bus faults. This makes the part well suited to maintaining installed Modbus-RTU style bridges and repeater nodes that cannot be redesigned.
מומלץ
SPI Peripheral Expansion and Monitoring
With its hardware SPI interface, the ATMEGA161L-4AC acts as an efficient master for serial EEPROMs, RTCs, ADCs, and display drivers in existing designs. The SPI bus plus the parallel external-memory interface let one low-cost MCU coordinate both fast local peripherals and memory-mapped I/O, using ALE and read/write control lines on the expansion port. The 4MHz external clock gives deterministic SPI SCK rates suitable for legacy data-acquisition cards where cycle-accurate sampling intervals are enforced by Timer/Counter interrupts. Three flexible Timer/Counters with compare modes timestamp events without core intervention, conserving the 1KB SRAM for data staging. In sustaining engineering, this part keeps 1990s-era SPI-based instrument control boards running without any layout or firmware changes.
מומלץ
Appliance and Consumer Equipment Control
White-goods and small-appliance controllers from the ATmega161 generation used exactly this L-grade part for its low-voltage tolerance and robust I/O count. The 35 general-purpose I/O lines cover keypads, seven-segment or LCD drive, triac controls, and door-interlock sensing without port expanders, while the 512-byte EEPROM stores cycle counters and user preferences through power interruptions. The programmable Watchdog Timer with its own internal oscillator guarantees recovery from lockups even if the main 4MHz external oscillator fails - an important safety behavior in heater and motor-control appliances. Because the die is unchanged from fielded units, a service replacement restores original firmware behavior, EMC characteristics, and safety qualifications, avoiding the recertification cost that any redesign would trigger.
מומלץ
Battery-Powered Low-Voltage Instruments
The 'L' speed grade of the ATMEGA161L-4AC is the low-voltage member of the family, characterized for operation down to approximately 2.7V at 4MHz, which makes it appropriate for 3-cell battery instruments designed to run without a 5V regulator stage. The external oscillator allows a low-cost 4MHz crystal chosen for accurate Timer/Counter timing during measurement windows, while idle and power-down sleep modes stretch battery life between readings. The real-time counter keeps long-interval logs independent of the main clock, and 512 bytes of EEPROM retains calibration constants across battery swaps. For repair of portable gauges, meters, and loggers, specifying the identical L-grade die preserves the validated power budget of the original design.
מומלץ
External-Memory Expandable Data Loggers
Unlike many small AVRs, the ATMEGA161L-4AC includes a full external memory expansion interface with address latching (ALE) and read/write strobes, letting designs extend beyond the internal 1KB SRAM using standard SRAM or memory-mapped peripherals. A data logger can thus dedicate internal SRAM as a fast ring buffer while cycling large external SRAM banks for extended event storage, timed by the three compare-mode Timer/Counters. The dual UARTs allow one port for sensor intake and a second for periodic offload to a host, and the Watchdog Timer guarantees logger recovery in unattended installations. For keeping aging logger platforms in service, the identical 44-TQFP device drops onto the existing board with the original 4MHz crystal and bus timing fully preserved.
מומלץ
סיכום מוצרים מומלצים
נתוני עזר הנדסיים עבור ATMEGA161L-4AC — השוואה, הנחיות תכנון ומידע על תאימות.
מדריך בחירה
השוואה עם חלופות
| פרמטר | מוצר זה | ATMEGA161L-4PI | ATMEGA162-16AU | ATMEGA16-16AU | ATMEGA128-16AU |
|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 44-TQFP (10x10 mm) | 44-TQFP (10x10 mm) - same | 44-TQFP (10x10 mm) - same | 44-TQFP (10x10 mm) - same | 44-TQFP (AVR TQFP family) |
| Max Speed | 4 MHz | 4 MHz | 16 MHz | 16 MHz | 16 MHz |
| Flash | 16 KB | 16 KB | 16 KB | 16 KB | 128 KB |
| SRAM | 1 KB | 1 KB | 1 KB | 1 KB | 4 KB |
| EEPROM | 512 bytes | 512 bytes | 512 bytes | 512 bytes | 4 KB |
| UART / USART Count | 2 | 2 | 2 | 1 | 2 |
| ADC | No | No | No | Yes, 8ch 10-bit | Yes, 8ch 10-bit |
| Lifecycle Status | Obsolete | Obsolete (broker stock only) | Active | Active | Active |
מבדילים עיקריים
- Dual UARTs in a 16KB AVR (לעומתATMEGA16-16AU)
- True ATmega161 silicon for legacy repair (לעומתATMEGA162-16AU)
- External memory expansion interface (לעומתATMEGA16-16AU)
הערות תכנון
The ATMEGA161L-4AC is an obsolete part sourced from broker inventory, so date codes and plating may vary between batches. Before committing to a production repair run, verify the package suffix (C = commercial grade, lead finish may be legacy tin-lead on older stock) against your RoHS obligations, and request date-code photos. The 'L' grade is rated at 4MHz only; do not substitute a higher-speed clock expecting full characterization, as the low-voltage speed limit is the binding constraint on this die.
The 44-TQFP (10x10 mm) footprint requires the 0.8mm pitch land pattern per the Atmel package drawing; keep the crystal within 15mm of XTAL1/XTAL2 with short return grounds, since the 4MHz external oscillator drives both UART baud-rate generators and any timing error shifts both serial ports simultaneously. Decouple both VCC pins (10 and 39) individually with 100nF ceramics placed within 5mm of each pin, and provide a solid ground plane for the SPI bus integrity.
Estimated: the L-grade ATmega161 is characterized for operation down to approximately 2.7V at 4MHz per the family datasheet. When powering from a 3V battery rail, budget for active current in the low single-digit mA range at 4MHz plus peripheral current for two UARTs and SPI. If your board must also accept a 5V supply during programming, check the ISP programmer voltage compatibility - programming a 3V system with a 5V-only ISP tool risks overstressing the die.
מידע על תאימות
Compliance status not stated in reviewed distributor listings. Commercial-grade ('C' suffix) legacy part may have tin-lead plating depending on date code; the industrial 4PI variant carries Pb-free plating per suffix coding. Request material declarations from the seller.