The MCU datasheet will tell you what the external signal timings are. The EPROM/EEPROM/NVRAM (whichever you finally use) datasheet will tell you what its requirements of external inputs are.

If you want to "do it right," you'll then measure the current timings with an oscilloscope.

Generally, a typical 805x MCU asserts ALE for a specified time, then negates it. A short time later, it asserts one of the three nPSEN, nRD, or nWR, depending on the nature of the cycle being performed. Information about when and for how long these signals are produced is in the MCU datasheet.

You can generate nRD with MOVX A,@DPTR, nWR with MOVX @DPTR,A, and nPSEN with MOVC A,@A+DPTR. That will enable you to measure the pulse widths produced by execution of each of these instructions. These signals are generated regardless of whether there's physical memory present where the DPTR points. I'd recommend that you point to an unoccupied region of your memory map so that the effect of reading and writing that space will be innocuous. Naturally, this will require that your MCU is able to execute the code that you write. The easiest way for you to do this will be to program the EEPROM to which you've already referred, with simple code to perform these operations and subsequently make your measurements. If you can program the internal code space in the MCU, then that might be an appropriate place for your code. However, the DPTR must point to an external code location in order to generate nPSEN.

RE