| Part Numbert | Mfg | Packt | D/C | Descriptiont | Qty | Company/Contact | |
| STK7709ST | 08+/09+ | 全新原装，欢迎订购！ | 123 |
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STK7709ST Datasheet
STK7709ST Price Output Port The output port pins may be controlled by the OPR, OPCR, MR and CR registers. Via appropriate programming they may be just another parallel port to external circuits, or they may represent many internal conditions of the UART. When this 8-bit port is used as a general purpose output port, the output port pins drive a state which is the complement of the Output Port Register (OPR). OPR(n) = 1 results in OP(n) = LOW and vice versa. Bits of the OPR can be individually set and reset. A bit is set by performing a write operation at address OxE with the accompanying data specifying the bits to be set (1 = set, 0 = no change). STK7709ST on stock The DS1218 Nonvolatile Controller performs the circuit functions required to battery back-up a RAM. First, a switch is provided to direct power from the battery or Vca supply, depending on which is greater. This switch has a voltage drop of less than 0.2V. The second function which the nonvolatile controller provides is power-fail detection. The DS1218 constantly monitors the Vcc supply. When Vca falls to 1.26 times the battery voltage, a precision comparator outputs a power-fail detect signal to the chip enable logic. The third function of write protection is accomplished by holding the chip enable output signal to within 0.2V of the Vca or battery supply, when a power-fail condition is detected.
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