Basic Operation
880
SPNU563A – March 2018
Copyright © 2018, Texas Instruments Incorporated
Analog To Digital Converter (ADC) Module
Once the device power-on reset is released, the ADC module controls the state of the ADxEVT pin.
•
Pull control:
The pull control can either be enabled or disabled by default (while system reset is active
and after it is released). The actual default state of the pull control is specified in the device datasheet.
The application can enable pull control by clearing the PDIS (pull control disable) bit in the
ADEVTPDIS register. In this case, if the PSEL (pull select) bit in the ADEVTPSEL register is set, the
pin will have a pull-up. If the PSEL bit is cleared, the pin will have a pull-down. If the PDIS bit is set in
the control register, there is no pull-up or pull-down on the pin.
NOTE:
Pull Behavior when ADxEVT is configured as output
If the ADxEVT pin is configured as output, then the pulls are disabled automatically. If the pin
is configured as input, the pulls are enabled or disabled depending on bit PDIS in the pull
disable register ADEVTPDIS.
•
Output buffer:
The ADxEVT pin can be driven as an output pin if the ADEVTDIR bit is set in the pin
direction control register.
•
Open-Drain Feature:
The open drain output capability is enabled via the ADEVTPDR control register.
The ADxEVT pin must be also configured to be an output pin for this mode.
–
The output buffer is enabled if a low signal is being driven on to the pin.
–
The output buffer is disabled if a high signal is being driven on to the pin.
22.2.8.2 Summary
The behavior of the output buffer, and the pull control is summarized in
. The input buffer for
the ADxEVT pins are enabled once the device power-on reset is released.
(1)
X = Don’t care
(2)
DIR = 0 for input, 1 for output
(3)
PULDIS = 0 for enabling pull control, 1 for disabling pull control
(4)
PULSEL = 0 for pull-down functionality, 1 for pull-up functionality
Table 22-5. Output Buffer and Pull Control Behavior for ADxEVT as GPIO Pins
System Reset
Active?
Pin Direction
(DIR)
(1) (2)
Pull Disable
(PDIS)
(1) (3)
Pull Select
(PSEL)
(1) (4)
Pull Control
Output Buffer
Yes
X
X
X
Enabled
Disabled
No
0
0
0
Pull down
Disabled
No
0
0
1
Pull up
Disabled
No
0
1
0
Disabled
Disabled
No
0
1
1
Disabled
Disabled
No
1
X
X
Disabled
Enabled