at94k10al ATMEL Corporation, at94k10al Datasheet - Page 141

• Manufacturer Part Number: at94k10al
• Description: At94k05al 5k - 40k Gates Of At40k Fpga With 8-bit Microcontroller, Up To 36k Bytes Of Sram And On-chip Jtag Ice
• Manufacturer: ATMEL Corporation

1138I–FPSLI–1/08
Figure 4-47. Block diagram of the 2-wire Serial Bus Interface
The CPU interfaces with the 2-wire Serial Interface via the following five I/O registers: the 2-wire
Serial Bit-rate Register (TWBR), the 2-wire Serial Control Register (TWCR), the 2-wire Serial
Status Register (TWSR), the 2-wire Serial Data Register (TWDR), and the 2-wire Serial Address
Register (TWAR, used in Slave mode).
The 2-wire Serial Bit-rate Register – TWBR
Bit
$1C ($3C)
Read/Write
Initial Value
SDA
SCL
7
TWBR7
R/W
0
OUTPUT
OUTPUT
INPUT
INPUT
6
TWBR6
R/W
0
5
TWBR5
R/W
0
TWAR
ADDRESS REGISTER
TWDR
STATUS DECODER
STATE MACHINE
SERIAL CLOCK
COMPARATOR
ARBITRATION
START/STOP
GENERATOR
DATA SHIFT
AND SYNC
REGISTER
4
TWBR4
R/W
0
STATUS
AND
AND
AT94KAL Series FPSLIC
3
TWBR3
R/W
0
2
TWBR2
R/W
0
TWCR
TWSR
REGISTER
REGISTER
CONTROL
CONTROL
STATUS
TIMING
AND
ACK
1
TWBR1
R/W
0
0
TWBR0
R/W
0
TWBR
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