11AA02UID datasheet(7/32 Pages) MICROCHIP

7 / 32 page

 2013 Microchip Technology Inc.

DS20005206A-page 7

11AA02UID

3.3

Acknowledge

An Acknowledge routine occurs after each byte is

transmitted, including the start header. This routine

consists of two bits. The first bit is transmitted by the

master, and the second bit is transmitted by the slave.

The Master Acknowledge, or MAK, is signified by trans-

mitting a ‘

1’, and informs the slave that the current

operation is to be continued. Conversely, a Not

Acknowledge, or NoMAK, is signified by transmitting a

‘0’, and is used to end the current operation (and initiate

the write cycle for write operations).

The slave Acknowledge, or SAK, is also signified by

transmitting a ‘

1’, and confirms proper communication.

However, unlike the NoMAK, the NoSAK is signified by

the lack of a middle edge during the bit period.

A NoSAK will occur for the following events:

• Following the start header

• Following the device address, if no slave on the

bus matches the transmitted address

• Following the command byte, if the command is

invalid, including Read, CRRD, Write, WRSR,

SETAL, and ERAL during a write cycle.

• If the slave becomes out of sync with the master

• If a command is terminated prematurely by using

a NoMAK, with the exception of immediately after

the device address.

See Figure 3.3 and Figure 3-4 for details.

If a NoSAK is received from the slave after any byte

(except the start header), an error has occurred. The

master should then perform a standby pulse and begin

the desired command again.

FIGURE 3-3:

ACKNOWLEDGE

ROUTINE

FIGURE 3-4:

ACKNOWLEDGE BITS

3.4

Device Addressing

A device address byte is the first byte received from the

master device following the start header. The device

address byte consists of a 4-bit family code, for the

11AA02UID this is set as ‘

1010’. The last four bits of

the device address byte are the device code, which is

hardwired to ‘

0000’.

FIGURE 3-5:

DEVICE ADDRESS BYTE

ALLOCATION

3.5

Bus Conflict Protection

To help guard against high current conditions arising

from bus conflicts, the 11AA02UID features a current-

limited output driver. The IOL and IOH specifications

describe the maximum current that can be sunk or

sourced, respectively, by the SCIO pin. The

11AA02UID will vary the output driver impedance to

ensure that the maximum current level is not exceeded.

Note:

A MAK must always be transmitted

following the start header.

Note:

When a NoMAK is used to end a

WRITE

WRSR instruction, the write cycle is not

initiated if no bytes of data have been

received.

Note:

In order to guard against bus contention, a

NoSAK will occur after the start header.

Master

Slave

MAK

SAK

MAK (‘1’)

NoMAK (‘0’)

SAK (‘1’)

NoSAK(1)

Note 1:

valid SAK.

A NoSAK is defined as any sequence that is not a

1010

000

MAK

SLAVE ADDRESS

SAK

11AA02UID 数据表(PDF) 7 Page - Microchip Technology

11AA02UID 数据表(HTML) 7 Page - Microchip Technology

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32

数据表下载

链接网址

11AA02UID 数据表(PDF) 7 Page - Microchip Technology

11AA02UID 数据表(HTML) 7 Page - Microchip Technology

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32

数据表 下载

链接网址

数据表下载