Rainbow-electronics DS2432 Manual do Utilizador

1 of 30 040201FEATURES 1128 bits of 5V EEPROM memory parti-tioned into four pages of 256 bits, a 64-bitwrite-only secret and up to 5 general purpose

PRELIMINARY DS243210 of 30Memory and SHA Functions Flow Chart (continued) Figure 7*1-Wire idle high for powerFrom Figure 72nd PartTo Figure 72nd PartT

PRELIMINARY DS243211 of 30Memory and SHA Functions Flow Chart (continued) Figure 733hCompute NextSecret ?Valid DataAddress ?YNBus Master TXTA1 (T7:T0)

PRELIMINARY DS243212 of 30Memory and SHA Functions Flow Chart (continued) Figure 755hCopy Scratch-pad ?YNBus Master TXTA1 (T7:T0),TA2 (T15:T8),E/S Byt

PRELIMINARY DS243213 of 30Memory and SHA Functions Flow Chart (continued) Figure 7A5hRead Auth.Page ?Bus Master TXTA1 (T7:T0), TA2 (T15:T8)YNYNAddress

PRELIMINARY DS243214 of 30Memory and SHA Functions Flow Chart (continued) Figure 7F0hRead Memory ?Address< 98h ?YNBus Master TXTA1 (T7:T0),TA2 (T15

PRELIMINARY DS243215 of 30Compute Next Secret [33h]Some applications may require a higher level of security than can be achieved by a single, directly

PRELIMINARY DS243216 of 30not write-protected the SHA engine will start and within 2.0 ms compute a new secret that is thenautomatically copied to th

PRELIMINARY DS243217 of 30Special attention is required when copying data to the register page. In order to prevent unintentionallocking of a special

PRELIMINARY DS243218 of 30that happens to reside in the scratchpad from a previous command as a challenge. The 160-bit MAC istransmitted in the same w

PRELIMINARY DS243219 of 30Read Memory [F0h]The read memory command may be used to read all memory except for the secret. Attempting to read thesecret

PRELIMINARY DS24322 of 30160-bit message authentication codes (MAC) when reading a memory page or to compute a new secret,instead of loading it. Appli

PRELIMINARY DS243220 of 30The variables A, B, C, D, E are initialized as follows:A := 67452301hB := EFCDAB89hC := 98BADCFEhD := 10325476hE:= C3D2E1F0h

PRELIMINARY DS243221 of 30HARDWARE CONFIGURATION Figure 8Open DrainPort PinRX = RECEIVETX = TRANSMIT100 ΩMOSFETVPUPRXTXTXRXDATARPU5 µATyp.BUS MASTER D

PRELIMINARY DS243222 of 30ROM FUNCTIONS FLOW CHART Figure 9From Figure 92nd PartTo Memory FunctionsFlow Chart (Figure 7)Master TX Bit 0Master TX Bit 6

PRELIMINARY DS243223 of 30ROM FUNCTIONS FLOW CHART (continued) Figure 9To Figure 91st PartFrom Figure 91st PartFrom Figure 91st PartTo Figure 9, 1st P

PRELIMINARY DS243224 of 30Search ROM [F0h]When a system is initially brought up, the bus master might not know the number of devices on the1-Wire bus

PRELIMINARY DS243225 of 301-WIRE SIGNALINGThe DS2432 requires strict protocols to ensure data integrity. The protocol consists of four types of sig-na

PRELIMINARY DS243226 of 30Read/Write Time SlotsThe definitions of write and read time slots are illustrated in Figure 11. The master initiates all tim

PRELIMINARY DS243227 of 30Read-data Time SlotVPULLUPVIH MINVPULLUP MINVIL MAX0VtLOWRtREC∞<≤ RECts1µs120ts60 SLOTµµ<≤s15ts1LOWRµµ<≤REGULAR SPE

PRELIMINARY DS243228 of 30With the Read Scratchpad command the CRC is generated by first clearing the CRC generator and thenshifting in the command co

PRELIMINARY DS243229 of 30ABSOLUTE MAXIMUM RATINGS*Voltage on Any Pin Relative to Ground -0.5V to +5.5VOperating Temperature -40°C to +85°CStorage T

PRELIMINARY DS24323 of 3064-BIT LASERED ROMEach DS2432 contains a unique ROM code that is 64 bits long. The first eight bits are a 1-Wire familycode.

PRELIMINARY DS243230 of 30AC ELECTRICAL CHARACTERISTICSOVERDRIVE SPEED (VPUP=2.8V to 5.25V; -40°C to +85°C)PARAMETER SYMBOL MIN TYP MAX UNITS NOTESTi

PRELIMINARY DS24324 of 301-WIRE CRC GENERATOR Figure 4X0X1X2X3X4X5X6X7X8Polynomial = X8 + X5 + X4 + 11stSTAGE2ndSTAGE3rdSTAGE4thSTAGE6thSTAGE5thSTAGE7

PRELIMINARY DS24325 of 30The secret can be installed either by copying data from the scratchpad to the secrets memory or bycomputation using the curre

PRELIMINARY DS24326 of 30number of data bits sent by the master is not an integer multiple of 8 or if the data in the scratchpad is notvalid due to a

PRELIMINARY DS24327 of 308 bytes, especially if the data is to be loaded as a secret. If the master sends less than eight data bytes anddoes not read

PRELIMINARY DS24328 of 30Memory and SHA Functions Flow Chart Figure 70FhWrite Scratch-pad ?MasterTX Reset ?Master TX Data ByteTo ScratchpadBus Master

PRELIMINARY DS24329 of 30Memory and SHA Functions Flow Chart (continued) Figure 7AAhRead Scratch-Pad ?DS2432 sets ScratchpadByte Counter = 0Bus Master