Microchip AVR SD family of low-cost 8-bit microcontrollers (MCUs) feature built-in functional safety (FuSa) mechanisms designed to meet Automotive Safety Integrity Level C (ASIL C) and Safety Integrity Level 2 (SIL 2) requirements, both of which mandate redundant safety checks.
Hardware safety features include a dual-core lockstep CPU, two ADCs for redundancy, an Error Correction Code (ECC) on all memories, a dedicated error controller module, error injection mechanisms, and voltage and clock monitors. The company further explains the AVR SD MCU meets Fault Detection Time Interval (FDTI) targets as low as 1 millisecond, and its functional safety management system has been certified by TÜV Rheinland.
Microchip AVR SD specifications:
- MCU core – AVR CPU in Dual-Core Lockstep (DCLS) clocked at up to 20 MHz
- Memory – 4 KB or 8KB SRAM with ECC
- Storage
- 32 KB or 64KB in-system-programmable Flash memory with ECC
- 256B EEPROM with ECC
- 512B of user row in Non-Volatile Memory (NVM) that can keep data during chip erase and be programmed while the device is locked
- 256B of Boot Row for cryptographic keys, only readable from the Boot Section
- I/Os and Peripherals
- Up to 25x GPIO pins (AVR32SD only, no data for AVR64SD)
- 6-channel Event System for predictable and CPU-independent inter-peripheral signaling
- 1x 16-bit Timer/Counter type A (TCA) with three compare channels for PWM and waveform generation
- Up to 4x 16-bit Timer/Counter type B (TCB) for capture and signal measurements
- 1x 12-bit Timer/Counter type D (TCD) optimized for power control
- 1x 16-bit Real-Time Counter (RTC) that can run from an external crystal or internal oscillator
- Up to 3x USARTs working as RS-485, LIN client, host SPI, or IrDA
- 2x SPI with host/client operation modes
- 2x I2C with simultaneous host/client operation (dual mode) and dual address match
- Configurable Custom Logic (CCL) with up to six programmable Lookup Tables (LUTs)
- 2x 10-bit, 170 ksps, ADC with independent voltage reference sources
- 1x 10-bit DAC
- 3x Analog Comparators (AC)
- Up to 2x Zero Cross Detectors (ZCD)
- Internal 1.024V, 2.048V, 4.096V and 2.500V voltage references, and external reference option
- System
- Power-on Reset (POR)
- Brown-out Detector (BOD) with programmable levels
- Voltage Regulator Monitor (VMON)
- Clock options
- High-precision internal oscillator with selectable frequency up to 20 MHz
- PLL up to 48 MHz for high-frequency operation of the TCD
- Internal 32.768 kHz oscillator
- External 32.768 kHz crystal oscillator
- External clock input
- High-frequency external crystal oscillator
- Clock Failure Detection (CFD)
- Clock Frequency Measurement (CFM)
- Single-pin Unified Program and Debug Interface (UPDI)
- Three sleep modes – Idle, Standby (configurable operation of selected peripherals), and Power-Down with full data retention
- Automated Cyclic Redundancy Check (CRCSCAN) program memory scan
- Verification of the Boot Flash section
- CRC-16-CCITT or CRC-32 (IEEE 802.3)
- External interrupt on all general-purpose pins
- System Integrity Functions
- Error Controller (ERRCTRL)
- Central interface for fault detection
- Fault handling in hardware according to programmable severity
- Optional Heartbeat output
- Optional tri-stating of all I/O pins in case of fault
- Parity on data buses
- Synchronous Watchdog Timer (SWDT)
- Watchdog Timer (WDT) with window mode and separate on-chip oscillator with clock failure detection
- Voltage Level Monitor (VLM) with interrupt
- Program and Debug Interface Disable (PDID)
- Error Controller (ERRCTRL)
- Supply Voltage – 2.7 to 5.5V
- Packages
- 20-pin SSOP
- 28-pin VQFN, SSOP, and SPDIP
- 32-pin VQFN and TQFP
- 48-pin TQFP, VQFN WF
- Temperature Ranges
- Industrial: -40°C to +85°C
- Extended: -40°C to +125°C
The AVR SD family is divided into two sub-families: the AVR32SD with 32 KB flash, 4KB SRAM, and 20-pin to 32-pin packages, and the AVR64SD with 64KB flash, 8KB SRAM, and 28-pin to 48-pin packages. The AVR32SD is currently in production, and the AVR64SD is planned for later.
Microchip says the AVR SD microcontrollers are compatible with the TÜV SÜD functional safety certified MPLAB XC8 Pro compiler and are supported by functional safety packages with documentation (Failure Modes, Effects and Diagnostic analysis report, Safety manual, Dependent Fault Analysis report), safety software, and compliance reports. Finally, engineers can evaluate the new 8-bit microcontroller with the AVR32SD32 Curiosity Nano development board equipped with a USB-C port, an on-board debugger, and two 21-pin GPIO headers, plus a few LEDs and a button.
Microchip AVR SD microcontrollers (AVR32SD20) start at $0.93 each in 5,000-unit quantities, with lower pricing for higher volumes. The development board can be purchased for $14.99, while the MPLAB XC8 Pro FuSa compiler (if needed) requires a cool $3,459.23 license fee. Further information can be found on the product page and the press release.
Thanks to TLS for the tip.
Jean-Luc started CNX Software in 2010 as a part-time endeavor, before quitting his job as a software engineering manager, and starting to write daily news, and reviews full time later in 2011.
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