DS28E05 Ver la hoja de datos (PDF) - Maxim Integrated

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DS28E05

1-Wire EEPROM

Maxim Integrated 

DS28E05

1-Wire EEPROM

Read Memory [F0h]

The Read Memory command is used to read the memory. The command needs a 16-bit starting address TA1, TA2. The

parameter byte specifies the lower address byte (TA1, T[6:0]) where the reading begins. After the parameter byte, the

master transmits TA2 (T[15:8]), which must be 00 to be valid. The reading can start at any valid starting address and

continue trough the end of the memory. If memory page 7 is read and the master continues reading, the resulting data

is FFh. The master can end the Read Memory command at any time by issuing a reset pulse.

Read Memory

Command Code

Parameter Byte

Restrictions

Protocol Variations

Error conditions

CS Byte

F0h

Starting memory address (Table 4).

None. This command can be issued at any time.

None.

Invalid parameter byte.

N/A

Table 4. Parameter Byte Bitmap

BIT 7

BIT 6

BIT 5

BIT 4

BIT 3

BIT 2

0

TA1

Note: The bit marked as 0 must be transmitted as 0 for the parameter byte to be valid.

BIT 1

BIT 0

1-Wire Bus System

The 1-Wire bus is a system that has a single bus master

and one or more slaves. In all instances the DS28E05

is a slave device. The discussion of this bus system is

broken down into three topics: hardware configuration,

transaction sequence, and 1-Wire signaling (signal types

and timing). The 1-Wire protocol defines bus transactions

in terms of the bus state during specific time slots, which

are initiated on the falling edge of sync pulses from the

bus master.

Hardware Configuration

The 1-Wire bus has only a single line by definition; it is

important that each device on the bus be able to drive

it at the appropriate time. To facilitate this, each device

attached to the 1-Wire bus must have open-drain or three-

state outputs. The 1-Wire port of the DS28E05 is open

drain with an internal circuit equivalent to that shown in

Figure 7.

BUS MASTER

Rx

Tx

OPEN-DRAIN

PORT PIN

VPUP

RPUP

DS28E05 1-Wire PORT

DATA

Rx

IL

Rx = RECEIVE

Tx = TRANSMIT

Tx

100Ω MOSFET

Figure 7. Hardware Configuration

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