HYUNDAI MicroElectronics |
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| GMS90X5XC Series | ||||||||
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| Function | ||||
| PLCC- |
| PDIP- |
| MQFP- | Output |
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| 44 |
| 40 |
| 44 |
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| The Address Latch Enable / |
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| ALE / | 33 |
| 30 |
| 27 | O | Program pulse |
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| PROG |
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| Output pulse for latching the low byte of the address | ||||
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| during an access to external memory. In normal | |||
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| operation, ALE is emitted at a constant rate of 1/6 the | |||
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| oscillator frequency, and can be used for external | |||
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| timing or clocking. Note that one ALE pulse is skipped | |||
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| during each access to external data memory. This pin | |||
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| is also the program pulse input (PROG) during | |||
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| EPROM programming. | |||
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| If desired, ALE operation can be disabled by setting | |||
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| bit 0 of SFR location 8EH. With this bit set, the pin is | |||
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| weakly pulled high. The ALE disable feature will be | |||
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| terminated by reset. Setting the | |||
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| no affect if the microcontroller is in external execution | |||
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| mode. |
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| / VPP | 35 |
| 31 |
| 29 | I | External Access Enable / Program Supply Voltage | |||
| EA |
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| EA must be external held low to enable the device to | |||
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| fetch code from external program memory locations | |||
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| 0000H to FFFFH. If EA is held high, the device | |||
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| executes from internal program memory unless the | |||
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| program counter contains an address greater than its | |||
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| internal memory size. This pin also receives the | |||
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| 12.75V programming supply voltage (VPP) during | |||
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| EPROM programming. | |||
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| Note; | however, that if any of the Lock bits are | ||
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| programmed, EA will be internally | ||
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| latched on reset. | ||
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| I/O | Port 0 |
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| Port 0 is an | |||
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| Port 0 pins that have 1s written to them float and can | |||
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| be used as | |||
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| Port 0 is also the multiplexed | |||
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| data bus during accesses to external program and | |||
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| data memory. In this application it uses strong internal | |||
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| code bytes during program verification in the | |||
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| GMS97X5X. External | |||
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| during program verification. | |||
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| VSS | 22 |
| 20 |
| 16 | - | Circuit ground potential | ||||
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| VCC | 44 |
| 40 |
| 38 | - | Supply terminal for all operating modes | ||||
| N.C. | 1,12 |
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| 6,17 | - | No connection | ||||
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| 23,34 |
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| 28,39 |
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8 | Jan. 2001 Ver 1.0 |