I had ever designed a 5 digs 8 by 8 dot matrix display that using 4094 to drive both the row and col. I mux the row instead of col so I just need to scan 8 lines instead of 25. My suggestion is that using 4094 is better than 165 because it got build in latch which is very useful for shifting data in background.
Besides there are several precations when using the 51 series mcu.
1. remember to assert some important control bits such as the timer control bits, the UART control bits, even the input ports ..etc.
2. remember to make software traps and watchdog ..etc.
3. If you want to catch the out of control program by software and use some ways to re-direct the control to location 0000h, make sure this software reset is identical to hardware RESET. That is to reload the value of all the registers, the control bits and most important the two F/Fs for interrupt priority control. How? just use two reti instructions!
Good luck and 73,Li.