System and Peripheral Control Registers
125
SPNU503C – March 2018
Copyright © 2018, Texas Instruments Incorporated
Architecture
2.5.1.1
SYS Pin Control Register 1 (SYSPC1)
The SYSPC1 register, shown in
and described in
, controls the function of the ECLK
pin.
Figure 2-6. SYS Pin Control Register 1 (SYSPC1) [offset = 00h]
31
16
Reserved
R-0
15
1
0
Reserved
ECPCLKFUN
R-0
R/W-0
LEGEND: R/W = Read/Write; R = Read only; -
n
= value after reset
Table 2-19. SYS Pin Control Register 1 (SYSPC1) Field Descriptions
Bit
Field
Value
Description
31-1
Reserved
0
Reads return 0. Writes have no effect.
0
ECPCLKFUN
ECLK function. This bit changes the function of the ECLK pin.
0
ECLK is in GIO mode.
1
ECLK is in functional mode as a clock output.
Note: Proper ECLK duty cycle is not assured until 1 ECLK cycle has elapsed after switching
into functional mode.
2.5.1.2
SYS Pin Control Register 2 (SYSPC2)
The SYSPC2 register, shown in
and described in
, controls whether the pin is an
input or an output when in GIO mode.
Figure 2-7. SYS Pin Control Register 2 (SYSPC2) [offset = 04h]
31
16
Reserved
R-0
15
1
0
Reserved
ECPCLKDIR
R-0
R/W-0
LEGEND: R/W = Read/Write; R = Read only; -
n
= value after reset
Table 2-20. SYS Pin Control Register 2 (SYSPC2) Field Descriptions
Bit
Field
Value
Description
31-1
Reserved
0
Reads return 0. Writes have no effect.
0
ECPCLKDIR
ECLK data direction. This bit controls the direction of the ECLK pin when it is configured to be in
GIO mode only.
0
The ECLK pin is an input.
Note: If the pin direction is set as an input , the output buffer is tristated.
1
The ECLK pin is an output.
Note: The ECLK pin is placed into GIO mode by clearing the ECPCLKFUN bit to 0 in the
SYSPC1 register.