the pins are the same on both 887 and 4550 chips. The 4550 does work with a 20mhz crystal but the timing is off. It does not record a proper time on the RTC and when I show the time on the LCD and do not pause for 1sec but a bit less then half a second and it always shows me 08:08:08:08. and the first few letters are missing on the lCD on the first line.

K