Freescale Semiconductor’s MCF51CN ColdFire V1 microcontroller tops the company’s Tower System development boards (see the figure). The $99 kit delivers a complete development package including a copy of the Freescale MQX real-time operating system.
The tower consists of a pair of “elevator” boards with four inexpensive PCI Express connectors. These connectors are found on almost every new PC motherboard, but they aren’t used for PCI Express. Instead, they provide a bus backplane for MCF51CN interfaces.
The approach allows for very inexpensive two-layer boards, including the MCU Module and the Peripheral Module, which includes connectors for various interfaces. The first “elevator” is used for signal distribution, while the second “elevator” board provides physical stability.
The system’s architecture makes it easy for designers to add boards, including custom interface boards. Software includes a 64-kbyte code limited version of Freescale’s CodeWarrior toolset that supports the MQX operating system and Ethernet stack.
The MCF51CN has a 50-MHz, 32-bit ColdFire core with 128 kbytes of flash and 24 kbytes of RAM. The external bus interface supports up to 2 Mbytes of off-chip storage. It also has a built-in 10/100 Ethernet interface with an internal media access controller (MAC) using an external physical layer (PHY). Peripherals include a 12-bit, 12-channel analog-to-digital converter (ADC), three serial communications interface (SCI) serial ports, two serial peripheral interface (SPI) ports, two I2C ports, and 70 general-purpose I/O (GPIO).
At $2.99, the MCF51CN is a relatively inexpensive chip so the $99 kit is a good match. Freescale has taken an interesting approach with its development kit. Following the old axiom, “Keep it simple,” Freescale has a winner.