NXP Semiconductors MC908QB8CDWER

Overview

MC908QB8CDWER from Freescale Semiconductor is an 8-bit HCS08-core microcontroller with 8 KB on-chip FLASH, 512 B RAM, and integrated peripherals including ADC10, ESCI, SPI, TIM, AWU, COP, and KBI. It operates at up to 8 MHz bus frequency, supports 2.7–5.5 V supply, and features Flash security protection via eight-byte monitor-mode unlock sequence stored at $FFF6–$FFFD.

For engineers reviewing the MC908QB8CDWER datasheet, MC908QB8CDWER pinout, MC908QB8CDWER application, or MC908QB8CDWER equivalent, this page delivers verified technical context, real-world use cases, pin-level design meaning, and validated alternative options for industrial control, appliance timing, and embedded sensor interface designs.

Technical Context

The MC908QB8CDWER implements the HCS08 CPU core with 16-bit address space, supporting indexed, extended, and relative addressing modes. Its memory map includes 8 KB FLASH (with block protection and mass/sector erase), 512 B RAM, and 128 B EEPROM-like data storage in FLASH.

Peripherals include a 10-bit ADC with 8 input channels and programmable conversion timing, an Auto Wakeup Module with configurable sleep intervals, and dual serial interfaces: ESCI (UART/LIN-capable) and SPI. Security enforcement denies monitor mode entry if ≥5 of the eight security bytes at $FFF6–$FFFD are zero.

Key Specifications

Pinout & Package

MC908QB8CDWER is housed in a 20-pin SOIC (Small Outline Integrated Circuit) package with 18 I/O pins, two power pins (VDD/VSS), and dedicated oscillator pins (OSC1/OSC2). Pin functions support multiplexed digital I/O, analog inputs, serial communication, and interrupt sources.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 8-bit microcontroller applications.

Compared with MC908QB8CDWER, MC908QY8CDTE offers identical Flash/RAM and core but omits KBI and uses a smaller package, while S9KEAZ128AMLH delivers significantly higher compute throughput and peripheral integration at the cost of migration effort and increased BOM complexity.

Availability

MC908QB8CDWER is available at Aetrix Electronics and suitable for home appliance control, industrial sensor nodes, automotive body electronics, and smart thermostat interfaces requiring stable component supply and long-term manufacturing continuity.

Supply support for MC908QB8CDWER 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) pioneered mixed-signal microcontrollers for cost-sensitive, low-power embedded systems across automotive, industrial, and consumer markets.

The MC908QB8CDWER belongs to the HCS08 family-designed for reliable, low-pin-count control applications where Flash security, integrated analog, and robust debug support are essential.

FAQ

What is the maximum bus frequency supported by the MC908QB8CDWER?

The MC908QB8CDWER supports a maximum bus frequency of 8 MHz. This is achieved using either the internal trimmed RC oscillator (calibrated to ±2%) or an external crystal/resonator up to 8 MHz. The bus clock is derived directly from the system oscillator source and governs instruction execution speed, peripheral timing, and ADC conversion rates in the MC908QB8CDWER.

How does the Flash security feature work in the MC908QB8CDWER?

The MC908QB8CDWER implements Flash security by requiring eight user-defined bytes programmed into memory locations $FFF6–$FFFD. During monitor mode entry, the host must transmit matching bytes; if five or more are $00, monitor mode access is denied. This prevents unauthorized firmware extraction while allowing legitimate debug access when correct keys are supplied - a critical safeguard in the MC908QB8CDWER's production firmware deployment.

Which analog inputs are available on the MC908QB8CDWER ADC10 module?

The MC908QB8CDWER ADC10 module supports eight analog input channels mapped to PTA0–PTA3 and PTB0–PTB3. Specifically, PTA0–PTA3 serve as AD0–AD3, while PTB0–PTB3 serve as AD4–AD7. These pins are multiplexed with digital I/O and require proper configuration of the ADCSC register and port direction registers before conversion. All channels share the same VREFH/VREFL references and support software or hardware triggering in the MC908QB8CDWER.

Does the MC908QB8CDWER support LIN communication?

Yes, the MC908QB8CDWER supports LIN communication through its Enhanced Serial Communications Interface (ESCI), which implements LIN 2.0 physical layer requirements including sync field detection, break delimiter recognition, and configurable bit timing. The ESCI module in the MC908QB8CDWER can operate as a LIN slave node without external transceiver components when paired with a standard LIN bus driver.

What low-power modes are available in the MC908QB8CDWER and how do they differ?

The MC908QB8CDWER supports Wait and Stop modes. In Wait mode, the CPU halts but peripherals (ADC, ESCI, TIM) remain clocked and functional; in Stop mode, nearly all clocks are disabled except for AWU and LVI, reducing current to ~1 µA. Both modes retain RAM contents, but only Stop mode enables ultra-low-power wake-up via AWU timer or IRQ edge - a key energy-saving feature in battery-operated MC908QB8CDWER deployments.