Port A Pullup Enable Register (Port_Ptape) - NXP Semiconductors MC9S08SU16 Reference Manual

Memory map and register definition

8.5.7 Port A Pullup Enable Register (PORT_PTAPE)

An internal pullup device can be enabled for each port pin by setting the corresponding
bit in one of the pullup enable registers (PTAPE[n], n=0-7). The internal pullup device is
disabled regardless of the state of the corresponding pullup enable register bit if:
• the pin is configured as an output direction
• by selecting any output peripheral functions
• input peripheral function like PWT
The internal pullup device is also disabled if the pin is controlled by an analog function.
If an SDA, SCL, RX, TX, KBI, or TCLK function is selected and enabled on a pin, the
pullup configuration for that pin still works. The internal pullup device is enabled when
pin select as BKGD/RESET function.
When configuring I2C to use "SDA(PTA5) and SCL(PTA4)"
pins, and if an application uses internal pullups instead of
external pullups, the internal pullups remain present setting
when the pins are configured as outputs, but they are
automatically disabled to save power when the output values
are low.
Address: 0h base + 18E0h offset = 18E0h
Bit 7
Read
Write
Reset
0
Field
PTAPE Pull Enable for Port A Bit
These bits determines if the internal pullup device is enabled for the associated PTA pin. For port A pins
that are configured as outputs, these bits have no effect and the internal pullup devices are disabled.
0 Internal pullup device disabled for port A bit n.
1 Internal pullup device enabled for port A bit n.
90
NOTE
6 5
0 0
PORT_PTAPE field descriptions
MC9S08SU16 Reference Manual, Rev. 5, 4/2017
4 3
PTAPE
0 0
Description
2 1
0 0
NXP Semiconductors
0
0