1 | Programming the Intel 8751H and 8751BH/87C51:
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2 |
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3 | I have the Intel databooks, and all of them say the same thing about
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4 | powering and clocking the chip with a typical crystal. Also they want
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5 | several pins pulled HI or LO, and then it programs just as an EPROM does
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6 | but the pinout is scattered around a bit differently, is all. I would
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7 | suppose you can grab the .pdf file from Intel that has all that for the
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8 | 8751 and others, like the 8748/9 and the 87C52 as well. They all use the
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9 | same scheme, and it is quite simple. I have several of these laying about,
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10 | and they have always been easy. I show for the 8751:
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11 |
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12 | 1) apply Vcc and Gnd to pins 40, 20
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13 | 2) xtal (4-6 MHz for programming only) to pins 19, 18 with caps to ground, 30pF
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14 | 3) address to Port1 pins and high byte to port 2.0-2.3
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15 | 4) data to port 0
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16 | 5) other pins per table below:
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17 |
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18 | *For the 8751BH and 87C51 :
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19 | This is the Quick-Pulse Algorithm, pulse is repeated 25 times/byte
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20 | address and then verified or failed by readback.
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21 | ALE/-PROG LO is the programming pulse, only 100us long
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22 | Vpp is 12.75V +/- 0.25V
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23 |
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24 | *For the 8751H :
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25 | The ALE/-PROG LO is the programming pulse, 50ms long,
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26 | Vpp is 21V +/- 0.25V
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27 | Verify chip after all programmed.
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28 |
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29 | RST -PSEN ALE/-PROG -EA/Vpp P2.7 P2.6 P3.6 P3.7
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30 | Pin 9 Pin 29 Pin 30 Pin 31 Pin 28 Pin 27 Pin 16 Pin 17
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31 | ------------------------------------------------------------------------
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32 | Program 1 0 0* Vpp 1 0 1 1
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33 | ------------------------------------------------------------------------
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34 | Verify 1 0 1 1 0 0 1 1
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35 | ------------------------------------------------------------------------
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36 | Program 1 0 0* Vpp 1 0 0 1
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37 | Encryption Tbl using addresses 0-1FHex
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38 | ------------------------------------------------------------------------
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39 | Program
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40 | Lock bits
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41 | x=1 1 0 0* Vpp 1 1 1 1
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42 | x=2 1 0 0* Vpp 1 1 0 0
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43 | ------------------------------------------------------------------------
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44 | Read 1 0 1 1 0 0 0 0
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45 | Signature
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46 | ------------------------------------------------------------------------
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47 |
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48 | Pinout:
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49 |
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50 | A0 P1.0 -1 40- Vcc
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51 | A1 P1.1 -2 39- P0.0 D0
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52 | A2 P1.2 -3 38- P0.1 D1
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53 | A3 P1.3 -4 37- P0.2 D2
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54 | A4 P1.4 -5 36- P0.3 D3
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55 | A5 P1.5 -6 35- P0.4 D4
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56 | A6 P1.6 -7 34- P0.5 D5
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57 | A7 P1.7 -8 33- P0.6 D6
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58 | RST -9 32- P0.7 D7
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59 | RXD P3.0 -10 31- -EA/Vpp
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60 | TXD P3.1 -11 30- ALE/-PROG
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61 | -INT0 P3.2 -12 29- -PSEN
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62 | -INT1 P3.3 -13 28- P2.7 A15* * not used for programming EPROM
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63 | T0 P3.4 -14 27- P2.6 A14* onboard, which is just 4K
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64 | T1 P3.5 -15 26- P2.5 A13*
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65 | -WR P3.6 -16 25- P2.4 A12*
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66 | -RD P3.7 -17 24- P2.3 A11
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67 | XTAL2-18 23- P2.2 A10
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68 | XTAL1-19 22- P2.1 A9
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69 | Vss -20 21- P2.0 A8
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70 |
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71 | And after an erasure, all but program and verify are optional, of course.
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72 | You should get the docs and read about the lock bits and the encryption
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73 | table, if you were producing a product, but for home use, it's not needed.
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74 | Have fun!
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75 | -Steve
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76 | --
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77 | -Steve Walz rstevew@armory.com ftp://ftp.armory.com:/pub/user/rstevew
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78 | -Electronics Site!! 1000 Files/50 Dirs!! http://www.armory.com/~rstevew
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79 | Europe:(Italy) http://ftp.cised.unina.it/pub/electronics/ftp.armory.com
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