Hello, I seen the C251 Development Tools, as in large programs RTOS is required; in C251, which RTOS we have to use; Same as RTX51 (Full) or not available.
To add some different opinion: When 8-bit is at it's end, why not switch to a 16-bit Controller with good design concept? The C166/C167/XC16x offer very good solutions for most embedded requirements. The big difference to ARM is that there even exist "small" devices such as the C161 or even the XC161 with a footprint not much larger than that of a 8-bit-Controller. Keil offers RTX166 and even ARTX166 as operating systems, and from Infineon comes a very mighty design sofware called "DAvE" for setting up the register values (the on-chip-periphery is very powerful)! The decision between a more "controller-like" chip like the C16x and a more "CPU-like" chip like the ARM should not only be influenced by the available OS, but also by the systems requirement. I programmed a motor control & data acquisition system using a single XC167 device to control a brushless DC motor and acquire measurement values from 16 channels (U and I), allone from the pin count this would have been impossible with an ARM, second would be the space: My controller board fits on a single 100x160mm board. Greetings, Axel Farr