SM8213AM datasheet(18/33 Pages) NPC

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SM8213AM

NIPPON PRECISION CIRCUITS—18

BS-test

This mode is used to test the RF stage operation, and

is only available from write mode. BS1 and BS3 are

held HIGH for RF stage testing.

After testing, BS-test mode is released using the

decoder set start command, and operation starts from

preamble mode.

Note that issuing the BACK-UP command is prohib-

ited in BS-test mode.

Start

This command is used to return to normal operation

from back-up, write and BS-test modes. Operation

always restarts from preamble mode.

Note the following points when setting commands:

Immediately after ATTN goes LOW

Commands send 8 SCK clock cycles to the

decoder and the received data is sent using 32

clock cycles immediately after ATTN goes LOW.

However, apart from the 8 clock cycles needed for

the command, 32 clock cycles are needed to

release ATTN. Note that during this time, there is

no guarantee of data.

When ATTN is HIGH

After command is transferred and until ATTN

goes LOW for the next transmit ready data signal,

the series processing should be such that it takes

less than {32

× (bit rate)} time. If it takes longer

than this amount of time, the command setting

may be delayed (relative to normal operation)

when ATTN goes LOW. Note that during this

time, there is no guarantee of data.

When ATTN goes HIGH (excluding write mode),

SCK is examined to determine if the signal is a

break, back-up, write or read command. During mes-

sage reception, ATTN is temporarily held HIGH if a

command is issued to set ATTN LOW. This delay

ensures that the data from the decoder is not misin-

terpreted. And in this case, even if ATTN keeps

LOW, transmitted receiving data is unstable.

Figure 10. Auxiliary operating mode timing

SCK

SDI

8-bit

× 1-byte = 8-bit unit time clock

8-bit

× 1-byte = 8-bit unit time data

Decoder Setting Data

Current Mode

Next Mode

Decoder Mode

Refer to the AC Characteristics section for detailed timing specifications.

START command : 66 bit time max

Others : 2 bit time max

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