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

VCC

VIAPO

VIL1MAX

APU = 1

APU = 0

0V

1-Wire LINE IS

tREC0

DISCHARGED

t1

t2

t3

Figure 4. Rising Edge Pullup During a Time Slot

1-Wire Port Configurations

The DS2465 allows adapting several timing parameters and the pullup resistor to the application’s needs. Each of these

parameters has its own 1-Wire Port Configuration register, located in the address range from 68h to 6Dh (Table 5). For

tRSTL, tMSP and tW0L the values for standard and overdrive speed can be adjusted independently. The lower nibble applies

to standard speed, the upper nibble to overdrive speed. The tREC0 and RWPU settings apply at both 1-Wire speeds. The

parameter tW1L can be adjusted for overdrive speed only; the standard speed value us fixed. For tREC0, RWPU and tW1L

the upper nibble has no function. See Table 6 for the conversion between binary code and parameter value.

After a device reset (power-up cycle, a low pulse at SLPZ, or initiated by the 1-Wire Master Reset command), the 1-Wire

Port Configuration registers are initialized to their default values. To change a port configuration, access the respective

register in I2C write mode and provide the new code as data byte. Starting at address 68h all port configurations can

be adjusted in a single write access. The new setting applies on the rising SCL edge of the data byte acknowledge bit,

provided that the 1-Wire line is not busy (1WB = 0). The upper 4 bits of the registers at 6Bh to 6Dh are not used. They

can be written, byte their value has no effect on the device operation.

Table 5. 1-Wire Port Configuration Address Details

ADDRESS

68h

69h

6Ah

6Bh

6Ch

6Dh

BIT 7

BIT 6

BIT 5

tRSTL Overdrive Speed (OD)

tMSP Overdrive Speed (OD)

tW0L Overdrive Speed (OD)

(not used, default 0000b)

(not used, default 0000b)

(not used, default 0000b)

BIT 4

BIT 3

BIT 2

BIT 1

tRSTL Standard Speed (STD)

tMSP Standard Speed (STD)

tW0L Standard Speed (STD)

tREC0 (speed independent)

RWPU (speed independent)

tW1L Overdrive Speed (OD)

BIT 0

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