View hd6473257p10 datasheet:

HD6473257P10 (1/4) IL08 ********** C-MOS 8-BIT 1-CHIP MICROCOMPUTER - TOP VIEW - 25 56 P50/TXD0 P10/A0 1 64 26 55 P51/RXD0 P11/A1 2 63 27 54 P52/SCK0 P12/A2 3 62 28 53 P53/TXD1 P13/A3 4 61 29 52 P54/RXD1 P14/A4 5 60 30 51 P55/SCK1 P15/A5 6 59 50 P16/A6 7 58 1 49 P60/FTCI P17/A7 8 57 2 P61/FTOA 9 56 3 47 P62/FTOB P20/A8 10 55 4 46 P63/FTI P21/A9 11 54 5 45 P64/IRQ0 P22/A10 12 53 644 P65/IRQ1 P23/A11 13 52 7 43 VDD P66/IRQ2 P24/A12 14 51 42 (+5V) P25/A13 15 50 31 41 P70/IS P26/A14 16 GND 49 32 40 P71/OS P27/A15 17 GND 48 33 P72/BUSY 18 47 34 57 P73/IOS P30/D0 19 46 35 58 P74/AS P31/D1 20 45 36 59 P75/WR P32/D2 21 44 37 60 P76/RD P33/D3 22 43 38 61 P77/WAIT P34/D4 23 42 62 P35/D5 24 41 8 63 RES P36/D6 25 40 64