Renesas' 32-bit RX6000 line takes a step forward with tools and development kits for the Renesas RX621 series. Leading the expansion of the ecosystem is Renesas' RX62N Demo Kit (Fig. 1). The board includes a 96MHz RX62N microcontroller (Fig. 2) with Ethernet, CAN and USB support. The system comes bundled with Renesas's own High-Performance Embedded Workshop (HEW) IDE along with a full GNU toolchain. The free KPIT GNU Tools is based on the Eclipse IDE.
The RX line of microcontrollers targets the same space as microcontrollers like Arm's Cortex-M3 series. Renesas has a number of features that challenge the competition including floating point support. It also has single cycle flash memory allowing the processor to run at speeds up to 100MHz with no wait states. The series supports flash sizes up to 2 Mbytes and 128 Kbytes of RAM. The demo board chip has 512 Kbytes for flash plus 32 Kbytes of data flash and 96 Kbytes of RAM. The typical complement of microcontroller peripherals includes 6 serial channels, I2C, CAN, and 2 SPI ports. On the analog side, the chip has an 8-channel 12-bit ADC and a 2-channel 10-bit DAC. The former can also be used as two 4-channel 10-bit ADCs. The CRC engine can come in handy as well.
The board has a number of interesting peripherals. Analog Devices’ ADXL345 digital iMEMS three-axis accelerometer for motion measurement. Other Analog Devices chips include the I2C ADT7420 serial digital temperature sensor and the ADMP401 digital iMEMS microphone. There is a 128 Mbit serial phase change memory from Micron Technology. The Ethernet PHY is National Semiconductor’s DP83640 10/100 Ethernet PHY with IEEE 1588 support. The 96 x 64-pixel, white LED backlit graphics LCD was supplied by Okaya.
Micrium's latest uC/OS III: The Real Time Kernel book for the RX62N by Jean Labrosses covers the operating system as well as specific sections on how it works with Renesas' microcontroller. The uC/OS III book (Fig. 3) is effectively matched with the RX62N Demo Kit. A bundled CD has a PDF version of the book as well as all the application code and a runtime version of the operating system. The OS is ROMable and optimized for 32-bit platforms although it still works with 8- and 16-bit microcontrollers. It is configurable at run-time and provides features like timestamped message posts. It has tick level task handling and an assembly language, optimizable scheduler. The latter requires a source license.
The DVD with the Renesas development kit also includes evaluation versions of other operating systems and tools. CMX provides compact operating systems and stacks for TCP/IP and flash file systems. FreeRTOS has its namesake RTOS that is open source and available with support via the compatible OpenRTOS. IAR Systems has its Embedded Workbench. Embedded Workbench can provide power debugging (see "Power Debugger Finds Hot Spots," on ElectronicDesign.com) with its RX development board (Fig. 4). IAR uses the JTAG debug interface to track power usage.
Developers looking to tie the RX processor to wireless networks can plug in one of Redpine Signals' Connect-io-n 802.11n SPI-based module. The low power, single stream module handles 802.11b/g/n networks. A bundled kit including wireless support is priced at $199.