DS1991

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1-WIRE SIGNALING

The DS1991 requires strict protocols to ensure data integrity. The protocol consists of four types of

signaling on one line: Reset Sequence with Reset Pulse and Presence Pulse, Write 0, Write 1 and Read

Data. All these signals except presence pulse are initiated by the bus master. The initialization sequence

required to begin any communication with the DS1991 is shown in Figure 10. A reset pulse followed by a

presence pulse indicates the DS1991 is ready to send or receive data given the correct ROM command

µs).

The bus master then releases the line and goes into receive mode (RX). The 1-Wire bus is pulled to a high

µs) and then transmits the presence pulse (t

µs).

ROM FUNCTIONS FLOW CHART Figure 9