AS3955 datasheet(70/111 Pages) AMSCO

номер детали	AS3955

подробное описание детали	NFC Forum Compliant Dynamic Tag

PDF	111 Pages

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производитель	AMSCO [ams AG]

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Page 70

ams Datasheet

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[v1-01] 2015-Apr-29

AS3955 − Detailed Description

Direct Command Mode

Direct Command Mode is comprised of one command byte and

argument byte. The two msb’s of command code 11b indicate

Direct Command Mode. The following six bits define command

code, sent MSB first. Last two bits in argument byte indicate

success of the direct command. Value 01h of the argument byte

indicates that command was accepted, while 02h indicates it

was rejected due to internal access priorities. The argument

byte does not provide information on timing of the command

execution.

Figure 79:

Sending a Direct Command over I²C

I²C Electrical Connection

The AS3955 has two built-in 3kΩ pull-up resistors on SDA and

SCL lines as shown on Figure 80 and used only in I²C mode. The

SPI pull-down bits in IO Configuration Register must be set 00h.

Figure 80:

I²C Interface with Built-In Pull-Up Resistors

Slave address

Mode Byte

SCL

SDA

00 0 0 0 0 xx

Argument byte

Slave address

RP=3kΩ

VP_IO

VSS

SDA

SCL

AS3955

AS3955 датащи(PDF) 70 Page - ams AG