• Journal of IKEEE
• /
• v.19 no.4
• /
• pp.625-631
• /
• 2015

In this paper, an 8051 microcontroller with application-specific instructions and I/O ports for data transmission is designed. The designed microcontoller includes two UART ports and one SMBus port to control external devices and to transmit data with them. Application-specific instruction is developed and added to the instruction set to exploit these I/O ports. So the designed microcontroller can perform multi-device control and multi-byte transmission. Also, it can reduce the code size of the application program. Especially, the designed microcontroller does not stall and can execute other programs during data transmission, which significantly increases its efficiency. Synthesized in 0.18 um technology, the area overhead due to application-specific instructions was negligible. Operations of all instructions and I/O ports were verified to run correctly on a FPGA board.