Rainbow-electronics DS2505 Manual de usuario

1 of 24 032201FEATURES 16384 bits Electrically Programmable ReadOnly Memory (EPROM) communicates withthe economy of one signal plus ground Unique,

DS250510 of 24MEMORY FUNCTION FLOW CHART Figure 5 (cont’d)

DS250511 of 24Note that the initial pass through the Read Status flow chart will generate a 16-bit CRC value that is theresult of clearing the CRC gen

DS250512 of 24With the next 24 read data time slots the master will receive the Redirection Byte of the next pagefollowed by a 16-bit CRC of the Redir

DS250513 of 24As the DS2505 receives this byte of data into the scratchpad, it also shifts the data into the CRC generatorthat has been preloaded with

DS250514 of 24responds with the data from the selected EPROM Status address sent least significant bit first. This bytecontains the logical AND of al

DS250515 of 24Hardware ConfigurationThe 1-Wire bus has only a single line by definition; it is important that each device on the bus be able todrive i

DS250516 of 24DS2505 EQUIVALENT CIRCUIT Figure 6BUS MASTER CIRCUIT Figure 7

DS250517 of 24ROM FUNCTIONS FLOW CHART Figure 8

DS250518 of 24Match ROM [55H]The Match ROM command, followed by a 64-bit ROM sequence, allows the bus master to address aspecific DS2505 on a multidro

DS250519 of 24(Figure 11) should be applied for 480 µs, after which the bus master returns the data line to an idle highstate controlled by the pullup

DS25052 of 24SILICON LABEL DESCRIPTIONThe DS2505 16-kbit Add–Only Memory identifies and stores relevant information about the product towhich it is as

DS250520 of 24READ/WRITE TIMING DIAGRAM Figure 10 (cont’d)NOTE:For read-data time slots the optimal sampling point for the master is as close as poss

DS250521 of 24PROGRAM PULSE TIMING DIAGRAM Figure 11CRC GENERATIONWith the DS2505 there are two different types of CRCs (Cyclic Redundancy Checks).

DS250522 of 24When reading the data memory of the DS2505 with the Extended Read Memory command, there are twosituations where a 16-bit CRC is transmit

DS250523 of 24ABSOLUTE MAXIMUM RATINGS*Voltage on any Pin Relative to Ground -0.5V to +12.0VOperating Temperature -40°C to +85°CStorage Temperature -5

DS250524 of 24NOTES:1. All voltages are referenced to ground.2. VPUP = external pullup voltage. If VPUP is lower than 3.0V the first byte read (any

DS25053 of 24protocol has been satisfied. This protocol is described in the ROM functions flow chart (Figure 8). The1-Wire bus master must first pro

DS25054 of 24HIERARCHICAL STRUCTURE FOR 1-WIRE PROTOCOL Figure 264-BIT LASERED ROM Figure 38-Bit CRC Code 48-Bit Serial Number 8-Bit Family Code (0B

DS25055 of 24EPROM STATUS BYTESIn addition to the 16384 bits of data memory the DS2505 provides 704 bits of Status Memory accessiblewith separate comm

DS25056 of 24The Status Memory address range of the DS2505 extends from 000 to 13FH. The memory locations008H to 01FH, 028H to 03FH, 048H to 0FFH and

DS25057 of 24MEMORY FUNCTION COMMANDSThe “Memory Function Flow Chart” (Figure 5) describes the protocols necessary for accessing thevarious data field

DS25058 of 24MEMORY FUNCTION FLOW CHART Figure 5

DS25059 of 24MEMORY FUNCTION FLOW CHART Figure 5 (cont’d)