PIC microcontrollers reach into 32-bit processing

By Robert Cravotta, Technical Editor -- 11/8/2007

Microchip’s PIC32 microcontroller family brings 32-bit processing options to the PIC line of processors. Microchip based the processors on the upgraded MIPS32 M4K core, and they maintain compatibility with the company’s existing line of PIC microcontrollers by supporting the same peripheral IP (intellectual-property) blocks, the same package pinouts, and the same development-tool environment. In addition to Microchip’s own MPlab development tools, 11 third-party tools vendors offer tools to support development for the PIC32 processors with IDEs (integrated development environments), compilers, debuggers, operating systems, and software IP. According to the company, the philosophy behind the PIC32 is to maintain the essence of a PIC microcontroller but offer it with more processing performance, more memory, and more choices of development tools.

The first seven devices in the family support operation as fast as 72 MHz with as much as 512 kbytes of flash memory and as much as 32 kbytes of RAM in a 64- or 100-pin TQFP that is peripheral- and pin-compatible with Microchip’s 16-bit PIC24 and dsPIC DSC (digital-signal-controller) microcontrollers. Some of the devices include as many as four channels of DMA with an integrated CRC (cyclic-redundancy-check) engine that can operate while the core is in idle mode. The family implements a single set of shadow registers of the 32-core register file. The M4K architecture that these devices employ can support as many as eight shadow sets for fast context switching, so there is room for expansion in the architecture to support fast switching for larger numbers of contexts. The hardware-vectored-interrupt controller supports as many as 63 interrupt vectors. Compatible peripherals include capture/compare/PWM timers; a 16-channel, 10-bit ADC; analog comparators; common serial interfaces; a watchdog timer, brownout, power-on-reset, and code protection; and multiple clock sources, including 8 MHz, 31 kHz, and an external source.

The PIC32 uses Microchip’s two-wire or JTAG debugging interface, and the on-chip debug supports as many as eight complex hardware breakpoints as well as nonintrusive, on-chip instruction trace. The trace module tracks the program counter, and the debugging software rebuilds much of the rest of the machine state during debugging. These devices are available now for general sampling, and the company plans production volumes for introduction during the second quarter of 2008. Prices for the PIC32 begin at $2.95 (10,000); the largest device, the PIC32MX360F512L delivers 512 kbytes of flash memory and 32 kbytes of RAM in a 100-pin TQFP for $5.30 (10,000). The devices support a –40 to +85°C temperature range.

Microchip’s MPlab 8.0 adds support for the PIC32, and it works with MPlab ICD (in-circuit debugger) 2 and MPlab Real ICE (in-circuit-emulator) debugging probes. The MPlab C32 C compiler uses the same peripheral libraries as the 16-bit PIC devices. The PIC32 DM320001 starter kit is available now for $49, and it includes sample code and projects, tutorials, and TCP/IP (Transmission Control Protocol/Internet Protocol) and FAT (file-allocation-table)-16 stacks. Microchip’s software libraries include source code for boot loader over IP, FTP (file-transfer-protocol) server, SMTP (Simple Mail Transfer Protocol) agent, and a Web server. Expansion boards supporting Ethernet, QVGA touchscreen display, and an I/O daughterboard will be available for the starter kit in the fourth quarter of this year.

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