2564 +----o----+ Vpp | 1 28| Vcc /CS1 | 2 27| /CS2 A7 | 3 26| Vcc A6 | 4 25| A8 A5 | 5 24| A9 A4 | 6 23| A12 A3 | 7 22| PD/PGM A2 | 8 21| A10 A1 | 9 20| A11 A0 |10 19| Q8 Q1 |11 18| Q7 Q2 |12 17| Q6 Q3 |13 16| Q5 Vss |14 15| Q4 +---------+ Pin 26 and 28 are connected internally -- only one is needed