246
XMEGA B [DATASHEET]
8291B–AVR–01/2013
19.8
Register Description – TWI
19.8.1 CTRL – Common Control Register
Bit 7:3 – Reserved
These bits are unused and reserved for future use. For compatibility with future devices, always write these bits to zero
when this register is written.
Bit 2:1 – SDAHOLD[1:0]: SDA Hold Time Enable.
Setting these bits to one enables an internal hold time on SDA with respect to the negative edge of SCL.
Table 19-1. SDA hold time.
Bit 0 – EDIEN: External Driver Interface Enable
Setting this bit enables the use of the external driver interface, and clearing this bit enables normal two-wire mode. See
for details.
Table 19-2. External driver interface enable.
Bit
7
6
5
4
3
2
1
0
–
–
–
–
–
SDAHOLD[1:0]
EDIEN
Read/Write
R
R
R
R
R
R/W
R/W
R/W
Initial Value
0
0
0
0
0
0
0
0
SDAHOLD[1:0]
Group Configuration
Description
00
OFF
SDA hold time off
01
50NS
Typical 50ns hold time
10
300NS
Typical 100ns hold time
11
400NS
Typical 400ns hold time
EDIEN
Mode
Comment
0
Normal TWI
Two-pin interface, slew rate control, and input filter.
1
External driver interface
Four-pin interface, standard I/O, no slew rate control, and no input
filter.
Содержание XMEGA B
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