Datasheet

Valid Read Sequences
Non-Valid Sequences
TPS65820
www.ti.com .............................................................................................................................................................. SLVS663B – MAY 2006 – REVISED APRIL 2008
The TPS65820 always ACKs its own address.
S hA1 bqA
Upon receiving hA1, TPS65820 starts at wherever the RAM address register is pointing. The START and the
STOP both act as priority interrupts. If the host has been interrupted and is not sure where it left off it can send a
STOP and reset the TPS65820 state machine to the WAIT state; once in WAIT state TPS65820 ignores all
activity on the SCL and SDA lines until it receives a START. A repeated START and START in the I
2
C
specification are both treated as a START.
S hA0 bqA hCMD bqA P
S hA0 bqA hCMD bqA S hA1 bqA bqDATA hN P
S hA1 bqA bqDATA hN P
Incremental read sequences
S hA1 bqA bqDATA hA bqDATA hA bqDATA hA bqDATA hA ... bqDATA hA P
START and non-hA0 or non-hA1 Address
A START followed by an address which is not bqA0 or bqA1 is NACKED
S hA_N bqN
Attempt to Specify Non-Allowed READ Address
If the CMD points to a non-allowed READ address (reserved registers), bq sends a NACK back to the host and it
does not load the address in the RAM address register. Note that TPS65820 NACKS whether a stop is sent or
not.
S hA0 bqA hCMD_N bqN P
S hA0 bqA hCMD_N bqN
Attempt to Specify Non-Allowed WRITE Address
If the host attempts to WRITE to a READ-ONLY or non-accessible address TPS65820 ACKS the CMD
containing the allowed READ address, loads the address into the address register and NACKS after the host
sends the next data byte. After issuing the NACK TPS65820 returns to WAIT state. A subsequent hA1 READ
could read this address.
S hA0 bqA hCMD bqA hDATA bN
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