DS2465P Просмотр технического описания (PDF) - Maxim Integrated

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DS2465P

SHA-256 Coprocessor with 1-Wire Master Function

Maxim Integrated 

ABRIDGED DATA SHEET

DS2465

SHA-256 Coprocessor with 1-Wire Master Function

1-Wire Triplet

Command Code

Parameter Byte

Usage

Other Notes

Command Restrictions

Error Conditions (Error Response)

MAC Notes

I2C Busy Duration

Command Duration

1-Wire Activity

Read Pointer Position

Master Status Bits Affected

Master Configurations Affected

1-Wire Port Configurations Affected

78h

Branch Direction (Table 23)

To perform a 1-Wire Search ROM sequence; a full sequence requires this command

to be executed 64 times to identify and address one device.

Generates three time slots: two read time slots and one write time slot at the 1-Wire

line. The type of write time slot depends on the result of the read time slots and the

direction byte.

• If the read time slots are 0 and 1, they are followed by a write-zero time slot.

• If the read time slots are 1 and 0, they are followed by a write-one time slot.

• If the read time slots are both 1 (error case), the subsequent write time slot is a

write-one.

• If the read time slots are both 0 (a typical case), the parameter byte determines the

type of the subsequent write time slot.

1-Wire activity must have ended before the DS2465 can process this command.

Command code is not acknowledged if 1WB = 1 at the time the command code is

received and the command is ignored.

N/A

None

3 x tSLOT + maximum 1.09µs, counted from the rising SCL edge of the parameter

byte acknowledge bit.

Begins maximum 1.09µs after the rising SCL edge of the parameter byte acknowledge

bit.

1-Wire Master Status register (for busy polling and data reading).

1WB (set to 1 for 3 x tSLOT), SBR is updated at the first tMSR, TSB and DIR are

updated at the second tMSR (i.e., at tSLOT + tMSR).

1WS, APU apply.

tW0L, tW1L, tREC0, and RWPU current values apply.

Table 23. Parameter Byte Bitmap

BIT 7

V

X = Don’t care

BIT 6

X

BIT 5

X

BIT 4

X

BIT 3

X

BIT 2

X

BIT 1

X

BIT 0

X

Bit 7: Bit value (V). This bit specifies the branch direction to be taken if both, the first and the second read time slot

read a 0. If V = 0, a write-zero time slot is generated. If V = 1, a write-one time slot is generated.

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