Description of Operation
16-8
ADSP-BF50x Blackfin Processor Hardware Reference
Bus Arbitration
The TWI controller initiates a master mode transmission (
MEN
) only when
the bus is idle. If the bus is idle and two masters initiate a transfer, arbitra-
tion for the bus begins. This is shown in
Figure 16-5
.
The TWI controller monitors the serial data bus (SDA) while
SCL
is high
and if SDA is determined to be an active logic 0 level while the TWI con-
troller’s data is a logic 1 level, the TWI controller has lost arbitration and
ends generation of clock and data. Note arbitration is not performed only
at serial clock edges, but also during the entire time
SCL
is high.
Start and Stop Conditions
Start and stop conditions involve serial data transitions while the serial
clock is a logic 1 level. The TWI controller generates and recognizes these
transitions. Typically start and stop conditions occur at the beginning and
at the conclusion of a transmission with the exception repeated start
“combined” transfers, as shown in
Figure 16-6
.
Figure 16-5. TWI Bus Arbitration
START
SCL (BUS)
TWI CONTROLLER
DATA
SECOND MASTER
DATA
SDA (BUS)
ARBITRATION
LOST
Summary of Contents for EZ-KIT Lite ADSP-BF506F
Page 50: ...Contents l ADSP BF50x Blackfin Processor Hardware Reference ...
Page 92: ...Development Tools 1 30 ADSP BF50x Blackfin Processor Hardware Reference ...
Page 110: ...Interface Overview 3 12 ADSP BF50x Blackfin Processor Hardware Reference ...
Page 236: ...Internal Flash Memory Control Registers 6 92 ADSP BF50x Blackfin Processor Hardware Reference ...
Page 650: ...Programming Examples 15 56 ADSP BF50x Blackfin Processor Hardware Reference ...
Page 804: ...Programming Examples 17 92 ADSP BF50x Blackfin Processor Hardware Reference ...
Page 1194: ...Programming Examples 24 90 ADSP BF50x Blackfin Processor Hardware Reference ...
Page 1256: ...ACM Registers A 50 ADSP BF50x Blackfin Processor Hardware Reference ...
Page 1264: ...Boundary Scan Architecture B 8 ADSP BF50x Blackfin Processor Hardware Reference ...