Hi, I am using the 8051 MCU in Multisim and am attempting to demonstrate the relationship between machine cycles and the 8051's clock signal. The problem I am having is that with the 8051 MCU internal oscillator set to 12MHz (done in the MCU Multisim model itself) it appears that it is not possible to trigger a logic analyser with the 8051's 12MHz clock and as a result the time associated with a machine cycle (ie. 12 clock cycles or 1us) is not accurate (when measured with a logic analyser instrument). Maybe there is something simple that I am missing here, but is it possible to disable the internal oscillator in the 8051 Multisim model so that the device is driven by an external oscillator circuit, or alternatively, is there any way in which the 8051 internal 12MHz oscillator/clock signal can be accessed in order to allow it to be used to trigger the logic analyser. In effect, I wish to be able to show that 1 machine cycle corresponds to 12 cycles of the 8051's clock signal (assuming that the model uses 12 cycles and not a variant model with a lesser cycle count). Any help on this would be greatly appreciated. Thanks
