Hi, I am new in 8051 so please bear with me for a minute. I am using a AT89C4051 to control a PLL chip. So basically I use 4 pins as CLK, DATA, LE and CE. The code development environment is Raisonance 6.1. The software is very simple and is written in C. After the main declaration I set some parameters and send these parameters to a function to send the data out serially. Ideally the controller should send these data once and stop. However, what I notice is that it will repeatedly send the data as if there is a loop asking it to do so. Can anyone think of a reason why it would do so? Thanks.