Programming the HM-76xxx PROMs The HM-76xxx PROMs are manufactured with all bits storing a logical "1" (output high). Any desired bit can be program-med to a logical "0" (output low) by following the simple procedure shown below. One may build his own programmer to satisfy the specifications described in the table, or use any of the commercially available programmers which can meet these specifications. PROGRAMMING SPECI FICATIONS RECOMMENDED SYMBOL PARAMETER MINIMUM OR TYPICAL MAXIMUM UNITS VIH Address Input 2.4 5.0 5.0 V Vll Voltage 11 I 0.0 0.4 0.5 V VPH 121 Programming/Verify 12.0 12.0 12.5 V VPll31 Voltage to VCC 4.5 4.5 5.5 V IllP Programming Input --300 -600 J.lA Low Current at VPH tr Programming IVCC I 1.0 1.0 10.0 J.ls If Voltage Rise and Fall Time 1.0 1.0 10.0 J.ls td Programming Delay 10 10 100 J.ls tp Programming Pulse Width (4) 90 100 110 Us P.D.C. Programming Duty Cycle 151 -50 60 % VOPE Output Voltage Enable 161 10.5 10.5 11.0 V VOPD Output Voltage Disable 0.0 5.0 5.5 V Ta Ambient Temperature -25 30 oC During programming the chip must be disabled for proper operation. NOTES: 1. No inputs should be left open for VIH. 2. VPH source must be capable of supplying one ampere. 3. It is recommended that dual verification be made at VPL min and VPL max. 4. Note step 9 in programming procedure. 5. Programming Duty Cycle applies to DIPs only, 6. VOPE source must be capable of supplying 10mA minimum. PROGRAMMING PROCEDURE 1. Address the PROM with the binary address of the word to be programmed. Address inputs are TTL compatible. An open circuit should not be used to address the PROM. 2. Bring the CEx input(s) high and the CEx input(s) low to disable the device. The disabling of the device during programming is an essential step in correctly program-ming all HARRIS PROMs. The chip enables are TTL compatible. An open circuit should not be used to dis-able the device. 3. Disable the programming circuitry by applying a voltage of VOPD to the outputs of the PROM. 4. Raise VCC to VPH with rise time less than or equal to tr. 5. After a delay equal to or greater than td apply a pulse with amplitude of VOPE and duration of tp to the output selected for programming. Note that the PROM is sup-plied with fuses intact, which generates an output high. Programming a fuse will cause the output to go low. 6. Other bits in the same word may be programmed while the VCC input is raised to VPH by applying output enable pulses to each output which is to be program-med. The output enable pulses must be separated by a minimum interval of td. 7. Lower VCC to 4.5 volts following a delay of td from last programming enable pulse applied to an output. 8. Enable the PROM for verification by applying VIL to CEx and VIH to CEx. 9. Repeat verification (step at VCC; 5.5 volts. 10. If any bit does not verify as programmed, repeat steps 2 through 9 until the bit has received a total of 1 ms of programming time. Bits which do not program within 1 ms are programming rejects. No further attempt to program these parts should be made. 11. Repeat steps 1 through 10 for all other bits to be pro-grammed in the PROM. 12. Programming rejects returned to the factory must be accompanied by data giving address, desired data, and actual output data of the location in which a program-ming failure has occur

http://www.bitsavers.org/components/harris/1984_Harris_Bipolar.pdf

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