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GMS90C32 数据表(PDF) 14 Page - Hynix Semiconductor |
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GMS90C32 数据表(HTML) 14 Page - Hynix Semiconductor |
14 / 59 page GMS90 Series 10 Oct. 2000 Ver 3.1a ALE / PROG 33 30 27 O The Address Latch Enable / Program pulse Output pulse for latching the low byte of the address during an access to external memory. In normal operation, ALE is emitted at a constant rate of 1/6 the oscillator frequency, and can be used for external timing or clocking. Note that one ALE pulse is skipped during each access to external data memory. This pin is also the program pulse input (PROG)during EPROM programming. In GMS9XC54/56/58: If desired, ALE operation can be disabled by setting bit 0 of SFR location 8EH. With this bit set, the pin is weakly pulled high. The ALE disable feature will be terminated by reset. Setting the ALE-disable bit has no affect if the microcontroller is in external execution mode. EA /VPP 35 31 29 I External Access Enable / Program Supply Voltage EA must be external held low to enable the device to fetch code from external program memory locations 0000H to FFFFH.If EA is held high, the device executes from internal program memory unless the program counter contains an address greater than its internal memory size. This pin also receives the 12.75V programming supply voltage (VPP)during EPROM programming. Note; however, that if any of the Lock bits are programmed, EA will be internally latched on reset. P0.0-P0.7 36-43 32-39 30-37 I/O Port 0 Port 0 is an 8-bit open-drain bidirectional I/O port. Port 0 pins that have 1s written to them float and can be used as high-impedance inputs. Port 0 is also the multiplexed low-order address and data bus during accesses to external program and data memory. In this application it uses strong internal pull-ups when emitting 1s. Port 0 also outputs the code bytes during program verification in the GMS97X5X. External pull-up resistors are required during program verification. VSS 22 20 16 - Circuit ground potential VCC 44 40 38 - Supply terminal for all operating modes N.C. 1,12 23,34 -6,17 28,39 - No connection Symbol Pin Number Input/ Output Function PLCC- 44 PDIP- 40 MQFP- 44 |
类似零件编号 - GMS90C32 |
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类似说明 - GMS90C32 |
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