With an eye on the lucrative automotive electronics market, Microchip Technology has launched its newest family of 8-bit PIC microcontrollers that supports the popular CAN 2.0B interface. Among the impressive features of the four new devices (PIC18F4680, PIC18F2680, PIC18F4585 and PIC18F2585) is the on-chip 48 Kbytes or 64 Kbytes of flash program memory in a tiny 28-pin package. Targeted automotive applications include body controllers, immobilizer receivers, occupant detection systems, power steering, anti-lock braking and stability sensing systems.
Automotive engineers have a growing need for cost-effective 8-bit microcontrollers with built-in CAN functionality and flexible flash memory, balanced with a requirement to consume less power and take up less space, said Cheri Keller, product marketing manager for PIC MCUs The new 28- and 40/44-pin MCUs help solve these design concerns with Microchip's on-chip ECAN module. The flash memory can be programmed "in-car."
The ECAN module enables multiple applications to be configured on a single node, with easier implementation to a software protocol bridge from a CAN network and a device to be re-used across different applications. The module also offers configurable transmit and receive (TX/RX) buffers that can be used for standard CAN operation or as FIFO registers, allowing one device to be used for multiple applications. There are three operational modes in one CAN engine: Mode 0 (legacy), Mode 1 (enhanced mode) and Mode 2 for the FIFO mode. Modes 1 and 2 support the DeviceNet protocol.
Legacy mode uses the same CAN interface as several other Microchip MCUs such as the MCP2510 and the PIC18C658. It offers seamless migration from existing PIC MCU CAN devices to the new PIC MCUs with the ECAN block. The enhanced operating mode provides additional resources and expanded functionality over and beyond what is offered in the legacy mode. In the FIFO mode, the receive buffers are not associated with a given acceptance filter. Messages are stored in the FIFO buffers based on the sequence in which they are received.
The new devices also employ Microchip's nanoWatt technology, which according to Keller offers the automotive industry attractive power management features. The technology improves battery life, which is a major cause of car failures today. Peripherals can be shut down to conserve power. In sleep mode, typical power consumption is as little as 0.1 microamp.
Code-compatible with existing PIC microcontrollers that feature CAN, the newest MCUs allow current customers to easily migrate to a more scalable CAN device with larger flash memory. The flash technology offers self-programming capability, allowing the microcontroller to be programmed after being placed in a circuit board and providing tremendous flexibility, reduced development time, increased manufacturing efficiency and faster time to market, according to Microchip.
Several improvements to clock switching are now incorporated into these devices. Clock switching no longer requires a sleep command. There are two internal oscillators. There is a so-called "sloppy" 32 KHz low-power RC oscillator; there is also a calibrated 8 MHz configurable RC oscillator. An internal RC can be run through a phase locked loop. This provides an up to 32 MHz internal clock source. Another feature is clock source selection on "wake-up."
Also embedded into the MCUs is an A/D converter with up to 11 channels x 10-bit resolution and 100 ksps, two analog comparators with internal voltage regulator circuitry, programmable brownout detect, and programmable low-voltage detect, one Capture/Compare/PWM module, one Enhanced Capture/Compare/PWM module. The MCUs also have 3K bytes of RAM and 1K byte of high-endurance EEPROM data memory on chip. The 28-pin devices have 25 I/O pins; the 40 pin devices have 36 I/O pins.
Serial I/O features include SPI and I2C modules, and a USART module with Local Interconnection Network (LIN) protocol support. There is In-Circuit Serial Programming (ICSP) technology for programming after being placed on a board. The units operate over a voltage range of 2.0 to 5.5 volts with an extended temperature range of -40°C to +125°C.
The four microcontrollers are available today for sampling and volume production is expected later this quarter, in the following package options; PIC18F2680 and PIC18F2585 are offered in 28-pin SDIP and SOIC, the PIC18F4680 and PIC18F4585 come in 40-pin PDIP, and 44-pin TQFP or QFN. In lots of 10K pieces, per piece pricing is as follows: the PIC18F2585 is $5.80; the 18F4585 and 18F2680 is each $6.27 while thee 18F4680 is $6.75.
All four Flash MCUs are supported by Microchip's development tools, including: MPLAB Integrated Development Environment (IDE), MPLAB C18 C compiler, MPLAB ICD2 In-Circuit Debugger, and MPLAB ICE 2000 In-Circuit Emulator. The PICDEM CAN LIN 2 Demonstration Board (Part Number: DM163011) shows the functionality of the integrated CAN module features on these devices and is available for $199.
For more information visit www.microchip.com