DS1920-F3 Maxim Integrated Products, DS1920-F3 Datasheet - Page 15

• Manufacturer Part Number: DS1920-F3
• Description: Temperature Ibutton
• Manufacturer: Maxim Integrated Products

DS1920
MEMORY AND CONTROL FUNCTIONS FLOW CHART (cont’ d) Figure 9
1-WIRE SIGNALING
The DS1920 requires strict protocols to ensure data integrity. The protocol consists of five types of
signaling on one line: Reset Sequence with Reset Pulse and Presence Pulse, Write 0, Write 1, Read Data
and Strong Pullup. All these signals except Presence Pulse are initiated by the bus master. The
initialization sequence required to begin any communication with the DS1920 is shown in Figure 10. A
Reset Pulse followed by a Presence Pulse indicates the DS1920 is ready to accept a ROM command. The
bus master transmits (TX) a Reset Pulse (t
, minimum 480 s). The bus master then releases the line
RSTL
and goes into receive mode (RX). The 1-Wire bus is pulled to a high state via the pullup resistor. After
detecting the rising edge on the 1-Wire line, the DS1920 waits (t
, 15-60 s) and then transmits the
PDH
Presence Pulse (t
, 60-240 s).
PDL
15 of 22