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NXP Semiconductors MC68HC705C8ACP
- Part No.:
- MC68HC705C8ACP
- Manufacturer:
- NXP Semiconductors
- Category:
- Microcontrollers
- Package:
- 40-DIP (0.600", 15.24mm)
- Datasheet:
-
MC68HC705C8ACP.pdf
- Description:
- IC MCU 8BIT 8KB OTP 40DIP
- Quantity:
- Payment:
- Shipping:
Inventory:3,655
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Product details
Overview
MC68HC705C8ACP from Freescale Semiconductor is an 8-bit OTP microcontroller featuring 8 KB on-chip EPROM/OTPROM, 192 bytes RAM, a 16-bit capture/compare timer, SCI and SPI serial interfaces, and four 8-bit I/O ports (PA–PD). It operates at up to 4 MHz internal bus speed with 5 V supply and supports low-power stop/wait modes. It targets embedded control in industrial sensors and legacy automotive subsystems.
For engineers reviewing the MC68HC705C8ACP datasheet, MC68HC705C8ACP pinout, MC68HC705C8ACP application, or MC68HC705C8ACP equivalent, key selection criteria include OTP memory retention, 40-pin PDIP package compatibility, COP watchdog configurability, and support for legacy M68HC05 instruction set software migration.
Technical Context
The MC68HC705C8ACP implements the M68HC05 CPU core with accumulator-based architecture, 16-bit program counter, and condition code register. Its memory map includes 8 KB of one-time-programmable ROM starting at $E000, 192 bytes of RAM ($0000–$00BF), and dedicated I/O register space.
It integrates dual serial peripherals: full-duplex SCI supporting asynchronous communication with programmable baud rate, and synchronous SPI supporting master/slave operation with configurable clock polarity and phase. The 16-bit timer supports input capture (edge-triggered event timestamping) and output compare (precise pulse generation).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| CPU Core | M68HC05 8-bit CISC core with 16-bit address bus and accumulator/index register architecture |
| Memory | 8 KB OTPROM (EPROM-equivalent, one-time programmable), 192 B RAM, no external memory interface |
| Max Bus Frequency | 4 MHz - determines instruction execution rate and peripheral timing margins |
| I/O Ports | Four 8-bit bidirectional ports (PA–PD); PD7 and PD5–PD0 are inputs only; PB supports interrupt-on-change |
| Serial Interfaces | SCI (asynchronous UART) + SPI (synchronous master/slave); both independently clocked and interrupt-capable |
| Timer | 16-bit free-running timer with input capture (TCAP) and output compare (TCMP) pins; supports event timing and PWM-like waveform generation |
| Power Modes | Run, Wait (CPU halted, peripherals active), Stop (all clocks stopped except RTC if present), and Data-Retention mode |
Pinout & Package
MC68HC705C8ACP is packaged in a 40-pin plastic dual in-line package (PDIP), case outline #824A per Motorola mechanical spec. Pin assignments match the standard 40-pin DIP footprint used across M68HC05 family devices.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VDD, VSS | Power supply and ground | Single 5 V supply required; decoupling capacitor mandatory at VDD pin per layout recommendation |
| OSC1, OSC2 | Crystal/resonator interface | Connects to external 32.768 kHz–4 MHz crystal or ceramic resonator; internal oscillator circuit provides system clock |
| RESET | Active-low reset input | Asynchronous external reset; initiates hardware reset sequence including stack pointer reload and vector fetch |
| IRQ | Interrupt request input | Edge-triggered (falling) external interrupt source; highest priority among maskable interrupts |
| TCAP, TCMP | Timer I/O pins | TCAP captures timestamp on signal edge; TCMP asserts output on timer match - enables precise timing control |
| PA0–PA7 | Port A I/O | 8-bit general-purpose bidirectional port; PA0–PA3 optionally serve as SCI serial lines (TXD/RXD) |
| PB0–PB7 | Port B I/O | 8-bit bidirectional port with interrupt-on-change capability per pin; PB0–PB1 optionally serve as SPI lines (MOSI/MISO) |
| PC0–PC7 | Port C I/O | 8-bit bidirectional port; PC0–PC1 optionally serve as SPI clock/select (SCK/SS) |
| PD0–PD5, PD7 | Port D inputs | 6-bit fixed-input port (PD6 is not bonded); used for status monitoring or switch inputs without output drive |
Key Features
| Feature | Design Value |
|---|---|
| On-chip OTPROM | 8 KB user-programmable nonvolatile memory eliminates need for external EPROM and reduces BOM cost |
| Configurable COP Watchdog | Programmable and non-programmable COP modes provide flexible fail-safe reset behavior for safety-critical loops |
| SCI with baud rate generator | Full-duplex UART with 13-bit baud rate divisor enables reliable RS-232/RS-485 communication at standard rates |
| SPI master/slave support | Hardware synchronous serial interface simplifies connection to ADCs, DACs, and display drivers without bit-banging overhead |
| Input capture with timestamping | Hardware edge-triggered capture on TCAP pin records exact timer value - essential for RPM sensing and pulse-width measurement |
Applications
| Industrial Sensor Node | Legacy Automotive Subsystem |
|---|---|
Use Scenario: Standalone temperature/humidity sensor with local display and serial reporting. IC Role / Device Role / Timing Role: Primary controller executing sensor polling, linearization, and ASCII protocol framing via SCI. Use Value: Integrated 8 KB OTPROM stores calibration coefficients and firmware; low-power wait mode extends battery life between readings. | Use Scenario: Dashboard illumination controller managing LED brightness based on ambient light and ignition state. IC Role / Device Role / Timing Role: Real-time I/O coordinator reading photoresistor input, driving PWM dimming outputs, and responding to CAN-linked commands via SCI gateway. Use Value: Port B interrupt-on-change detects ignition transition; capture/compare timer generates stable 100 Hz PWM for flicker-free dimming. |
| Motor Control Interface | Point-of-Sale Peripheral |
Use Scenario: Brushed DC motor driver board with overcurrent protection and speed feedback. IC Role / Device Role / Timing Role: Closed-loop controller using TCAP to measure back-EMF period and TCMP to adjust commutation timing. Use Value: Hardware timer capture eliminates software jitter in RPM calculation; 4 MHz bus speed ensures timely response to fault conditions. | Use Scenario: Barcode scanner interface module translating TTL-level scan data to RS-232 for receipt printers. IC Role / Device Role / Timing Role: Protocol translator buffering and framing incoming parallel scan data into SCI-transmitted ASCII packets. Use Value: On-chip RAM buffers multi-character barcodes; SCI baud rate register allows field-adjustable communication speed to match host printer. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar microcontroller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MC68HC705P6ACP | 4 KB OTPROM, no SPI, only SCI; same 40-pin PDIP package and M68HC05 core | Lacks SPI peripheral - unsuitable for systems requiring synchronous sensor or display interfacing | Select when cost-sensitive designs require only UART communication and reduced code size |
| MC68HC705B16CP | 16 KB OTPROM, added 8-bit A/D converter, same timer/SCI/SPI peripherals | Includes analog front-end - enables direct sensor voltage acquisition without external ADC | Choose when design requires analog signal conditioning alongside digital control and serial comms |
Compared with MC68HC705C8ACP, the P6A offers lower memory and fewer peripherals at lower cost, while the B16 adds ADC functionality but increases unit price and power consumption - selection depends on whether SPI is mandatory and whether analog inputs are needed.
Availability
MC68HC705C8ACP is available at Aetrix Electronics and suitable for industrial sensor nodes, legacy automotive subsystems, and motor control interfaces requiring stable component supply and long-term obsolescence management.
Supply support for MC68HC705C8ACP includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.
Manufacturer
Freescale Semiconductor (now part of NXP Semiconductors) was a leading designer of embedded controllers, analog, and RF solutions for automotive, industrial, and networking markets.
The MC68HC705C8ACP belongs to the M68HC05 microcontroller family, designed for cost-sensitive, low-pin-count embedded control applications where OTP memory, integrated peripherals, and M6805 software compatibility were critical.
FAQ
What is the maximum operating frequency of the MC68HC705C8ACP?
The MC68HC705C8ACP supports a maximum internal bus frequency of 4 MHz, derived from its crystal oscillator input (typically 4 MHz or 3.6864 MHz). This defines the instruction execution rate and timing constraints for all on-chip peripherals including SCI baud generation and timer overflow intervals. The device does not support external clock sources above this rated frequency.
Does the MC68HC705C8ACP support in-circuit programming?
No, the MC68HC705C8ACP contains one-time-programmable (OTP) EPROM memory and requires external UV-erasable or high-voltage programming equipment prior to soldering. It lacks on-chip debug interfaces or bootloader ROM for in-system reprogramming. Firmware updates necessitate physical device replacement.
Which I/O ports on the MC68HC705C8ACP support interrupt-on-change functionality?
Only Port B (PB0–PB7) supports interrupt-on-change functionality on the MC68HC705C8ACP. Each PB pin can be individually enabled to trigger an interrupt on logic level transition, making it suitable for keypad scanning or status change detection. Ports PA, PC, and PD do not offer this feature.
Can the MC68HC705C8ACP operate from a 3.3 V supply?
No, the MC68HC705C8ACP is specified only for 5.0 V ±10% operation per its DC electrical characteristics table. While some later variants like the MC68HSC705C8A support 3.3 V, the standard MC68HC705C8ACP requires a 5 V supply and is not guaranteed to function correctly at 3.3 V.
What is the purpose of the VPP pin on the MC68HC705C8ACP?
The VPP pin (Pin 1) on the MC68HC705C8ACP supplies the elevated programming voltage (typically 12.5 V) required during OTPROM programming. It is not used during normal operation and must be left unconnected or grounded when the device is running in application mode.
MC68HC705C8ACP Specifications
- Product attributes
- Attribute value
- Manufacturer:
- NXP Semiconductors
- Package/Case:
- 40-DIP (0.600", 15.24mm)
- Series:
- HC05
- Packaging:
- Tube
- Product Status:
- Obsolete
- Programmable:
- Not Verified
- Core Processor:
- HC05
- Core Size:
- 8-Bit
- Speed:
- 2.1MHz
- Connectivity:
- SCI, SPI
- Peripherals:
- POR, WDT
- Number of I/O:
- 24
- Program Memory Size:
- 8KB (8K x 8)
- Program Memory Type:
- OTP
- EEPROM Size:
- -
- RAM Size:
- 304 x 8
- Voltage - Supply (Vcc/Vdd):
- 3V ~ 5.5V
- Data Converters:
- -
- Oscillator Type:
- Internal
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
MC68HC705C8ACP FAQ
1.How can I place an order for MC68HC705C8ACP through Aetrix?
Please submit a Request for Quotation (RFQ) for MC68HC705C8ACP on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for MC68HC705C8ACP reliable?
The price and inventory of MC68HC705C8ACP are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MC68HC705C8ACP is usually 5 days.
3.What payment methods are accepted for MC68HC705C8ACP?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MC68HC705C8ACP transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MC68HC705C8ACP?
MC68HC705C8ACP orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MC68HC705C8ACP order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for MC68HC705C8ACP?
For technical support, including MC68HC705C8ACP datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MC68HC705C8ACP requirements.
6.How does Aetrix verify that MC68HC705C8ACP is sourced from the original manufacturer or authorized distributors?
All MC68HC705C8ACP products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that MC68HC705C8ACP meets industry standards.
7.What is the process for return or replacement of MC68HC705C8ACP?
All MC68HC705C8ACP units undergo pre-shipment inspection (PSI). If there is an issue with MC68HC705C8ACP, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The MC68HC705C8ACP part is unused and in its original packaging.
Return procedure for MC68HC705C8ACP:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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