I2C Registers
21.4.1.25 I2C_SYSTEST Register (offset = BCh) [reset = 0h]
I2C_SYSTEST is shown in
and described in
.
CAUTION: Never enable this register for normal I2C operation This register is used to facilitate system-
level tests by overriding some of the standard functional features of the peripheral. It allows testing of SCL
counters, controlling the signals that connect to I/O pins, or creating digital loop-back for self-test when the
module is configured in system test (SYSTEST) mode. It also provides stop/non-stop functionality in the
debug mode.
Figure 21-40. I2C_SYSTEST Register
31
30
29
28
27
26
25
24
Reserved
R-0h
23
22
21
20
19
18
17
16
Reserved
R-0h
15
14
13
12
11
10
9
8
ST_EN
FREE
TMODE
SSB
Reserved
SCL_I_FUNC
R/W-0h
R/W-0h
R/W-0h
R/W-0h
R-0h
R-0h
7
6
5
4
3
2
1
0
SCL_O_FUNC
SDA_I_FUNC
SDA_O_FUNC
Reserved
SCL_I
SCL_O
SDA_I
SDA_O
R-0h
R-0h
R-0h
R-0h
R-0h
R-0h
R-0h
R-0h
LEGEND: R/W = Read/Write; R = Read only; W1toCl = Write 1 to clear bit; -n = value after reset
Table 21-33. I2C_SYSTEST Register Field Descriptions
Bit
Field
Type
Reset
Description
31-16
Reserved
R
0h
15
ST_EN
R/W
0h
System test enable.
This bit must be set to 1 to permit other system test registers bits to
be set.
Value after reset is low.
0x0 = Normal mode. All others bits in register are read only.
0x1 = System test enabled. Permit other system test registers bits to
be set.
3757
SPRUH73H – October 2011 – Revised April 2013
I2C
Copyright © 2011–2013, Texas Instruments Incorporated