Datasheet

N2HET Functional Description www.ti.com
The following apply if the device is under reset:
• Pull control: The reset pull control on the pins is enabled and a pulldown is configured.
• Input buffer: The input buffer is enabled.
• Output buffer: The output buffer is disabled.
The following apply if the device is out of reset:
• Pull control: The pull control is enabled by clearing the corresponding bit in the N2HET Pull Disable
Register (HETPULDIS). In this case, if the corresponding bit in the N2HET Pull Select Register
(HETPSL) is set, the pin will have a pull-up; if the bit in the N2HET Pull Select Register (HETPSL) is
cleared, the pin will have a pull-down. If the bit in the N2HET Pull Disable Register (HETPULDIS) is
set, there is no pull-up or pull-down on the pin.
• Input buffer: The input buffer is disabled only if the pin direction is set to input AND the pull control is
disabled AND pull down is selected as the pull bias. In all other cases, the input buffer is enabled.
NOTE: The pull-disable logic depends on the pin direction. If the 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 the pull disable register bit.
• Output buffer: A pin can be driven as an output pin if the corresponding bit in the N2HET Direction
Register (HETDIR) is set AND the open-drain feature (N2HET Open Drain Register (HETPDR)) is not
enabled. See Section 23.2.5.15 for more details.
The behavior of the input buffer, output buffer, and the pull control is summarized in Table 23-9. When an
input buffer is disabled, it appears as a logic low to on-chip logic.
Table 23-9. Input Buffer, Output Buffer and Pull Control Behavior
(1)
Device Pin
under Direction Pull Disable Pull Select
Reset? (DIR) (PULDIS) (PULSEL) Pull Control Output Buffer Input Buffer
Yes X X X Device- and module-specific Disabled Disabled
No 0 0 0 Pull down Disabled Enabled
No 0 0 1 Pull up Disabled Enabled
No 0 1 0 Disabled Disabled Disabled
No 0 1 1 Disabled Disabled Enabled
No 1 X X Disabled Enabled Enabled
(1)
X = Don’t care
23.2.5.15 Open-Drain Feature
The following apply if the open-drain feature is enabled on a pin, that is, the corresponding bit in the
N2HET Open Drain Register (HETPDR) is set
• Output buffer is enabled if a low signal is being driven internally to the pin.
• The output buffer is disabled if a high signal is being driven internally to the pin.
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High-End Timer (N2HET) Module SPNU562–May 2014
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