>gdi XTAL <n>
where, <n>, by default, is a hexadecimal number, representing the simulated frequency of an external oscillator. Adding the suffix `t' to the 'n' parameter forces the input value to be interpreted as base 10.
>gdi XTAL
Brings up an input window. The default base for this input value is 10. However, this value can be forced to a hexadecimal format through use of the suffix `h'.