Datasheet

Status Code
(TWSRn)
Prescaler Bits
are 0
Status of the 2-wire Serial
Bus and 2-wire Serial
Interface Hardware
Application Software Response Next Action Taken by TWI
Hardware
To/from
TWD
To TWCRn
STA STO TWINT TWEA
0x58 Data byte has been received;
NOT ACK has been returned
Read data
byte
1 0 1 X Repeated START will be
transmitted
0 1 1 X STOP condition will be
transmitted and TWSTO Flag
will be reset
1 1 1 X STOP condition followed by a
START condition will be
transmitted and TWSTO Flag
will be reset
Figure 23-14. Formats and States in the Master Receiver Mode
S SLA R A DAT A A
0x08 0x40 0x50
SLA R
0x10
A P
0x48
A or A
0x38
Other master
contin ues
0x38
Other master
contin ues
W
A
0x68
Other master
contin ues
0x78 0xB0
To corresponding
states in sla v e mode
MR
MT
Successfull
reception
from a sla v e
receiv er
Next transf er
star ted with a
repeated star t
condition
Not ac kno wledge
received after the
slave address
Arbitration lost in sla v e
address or data b yte
Arbitration lost and
addressed as sla v e
DAT A A
n
From master to sla v e
From slave to master
Any number of data b ytes
and their associated ac kno wledge bits
This number (contained in TWSR) corresponds
to a defined state of the 2-Wire Ser ial Bus. The
prescaler bits are z ero or mask ed to z ero
PDATA A
0x58
A
R
S
Atmel ATmega644A [DATASHEET]
Atmel-42716C-ATmega644A_Datasheet_Complete-10/2016
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