Atmel Xplained Evaluation Board AT32UC3A3-XPLD AT32UC3A3-XPLD データシート
製品コード
AT32UC3A3-XPLD
493
32072H–AVR32–10/2012
AT32UC3A3
23.9.3
SMBus Timing Register
Name:
SMBTR
Access Type:
Read/Write
Offset:
0x08
Reset Value:
0x00000000
• EXP: SMBus Timeout Clock Prescaler
Used to specify how to prescale the TIM and TLOWM counters in SMBTR. Counters are prescaled according to the following
formula
• THMAX: Clock High Maximum Cycles
Clock cycles in clock high maximum count. Prescaled by SMBTR.EXP. Used for bus free detection. Used to time T
HIGH:MAX
.
NOTE: Uses the prescaler specified by CWGR, NOT the prescaler specified by SMBTR.
• TLOWM: Master Clock Stretch Maximum Cycles
Clock cycles in master maximum clock stretch count. Prescaled by SMBTR.EXP. Used to time T
LOW:MEXT
• TLOWS: Slave Clock Stretch Maximum Cycles
Clock cycles in slave maximum clock stretch count. Prescaled by SMBTR.EXP. Used to time T
LOW:SEXT
.
31
30
29
28
27
26
25
24
EXP
-
-
-
-
23
22
21
20
19
18
17
16
THMAX
15
14
13
12
11
10
9
8
TLOWM
7
6
5
4
3
2
1
0
TLOWS
f
prescaled SMBus
,
f
CLKTWIM
2
EXP
1
+
(
)
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=