DS1065
PROGRAMMING
Normally when power is applied to the supply voltage pin the device will enter its normal operating
mode, following the power-on reset sequence. However the device can be made to enter a programming
mode if a pullup resistor is connected between IN/OUT and the supply voltage pin prior to power-up.
The method used for programming is a variant of the 1-WireTM protocol used on a number of Dallas
Semiconductor products.
HARDWARE
The hardware configuration is shown in the diagram. A bus master is used to read and write data to the
DS1065’s internal registers. The bus master may have either an open-drain or TTL-type architecture.
Figure 11
Programming mode is entered by simply powering up the DS1065 with a pullup of approximately 5kꢀ.
This will pull the IN/OUT pin above VIH on power-up and initiate the programming mode, causing the
DS1065 to internally release the IN/OUT pin after t STAB and allow the pullup resistor to pull up the pin to
the supply rail and await the Master Tx Reset pulse (see diagram).
NOTE:
To ensure normal operation any external pullup applied to IN/OUT must be greater than 20 kꢀꢁin value.
This will cause the IN/OUT pin to remain below VIH on power-up, resulting in normal operation at the
end of tSTAB
.
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DALLAS [ DALLAS SEMICONDUCTOR ]
