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Chapter 2 Port Integration Module (S12XEPIMV1)
MC9S12XE-Family Reference Manual , Rev. 1.07
108
Freescale Semiconductor
2.3.13
S12X_EBI ports, BKGD pin Pull-up Control Register (PUCR)
1
Read: Anytime. In emulation modes, read operations will return the data from the external bus, in all other modes the data
source is depending on the data direction value.
Write: Anytime. In emulation modes, write operations will also be directed to the external bus.
Table 2-12. DDRE Register Field Descriptions
Field
Description
7-2
DDRE
Port E Data Direction
—
This register controls the data direction of pins 7 through 2.
The external bus function controls the data direction for the associated pins. In this case the data direction bits will
not change.
When operating a pin as a general purpose I/O, the associated data direction bit determines whether it is an input
or output.
1 Associated pin is configured as output.
0 Associated pin is configured as high-impedance input.
1-0
Reserved
—
Port E bit 1 (associated with IRQ) and bit 0 (associated with XIRQ) cannot be configured as outputs. Port E, bits 1
and 0, can be read regardless of whether the alternate interrupt function is enabled.
Address 0x000C (PRR)
Access: User read/write
1
1
Read:Anytime in single-chip modes.
Write:Anytime, except BKPUE which is writable in Special Test Mode only.
7
6
5
4
3
2
1
0
R
PUPKE
BKPUE
0
PUPEE
PUPDE
PUPCE
PUPBE
PUPAE
W
Reset
1
1
0
1
0
0
0
0
= Unimplemented or Reserved
Figure 2-11. S12X_EBI ports, BKGD pin Pull-up Control Register (PUCR)
Table 2-13. PUCR Register Field Descriptions
Field
Description
7
PUPKE
Pull-up Port K Enable
—Enable pull-up devices on all Port K input pins
This bit configures whether pull-up devices are activated, if the pins are used as inputs. This bit has no effect if the
pins are used as outputs. Out of reset the pull-up devices are enabled.
1 Pull-up devices enabled.
0 Pull-up devices disabled.
6
BKPUE
BKGD pin pull-up Enable
—Enable pull-up devices on BKGD pin
This bit configures whether a pull-up device is activated, if the pin is used as input. This bit has no effect if the pin is
used as outputs. Out of reset the pull-up device is enabled.
1 Pull-up device enabled.
0 Pull-up device disabled.
5
Reserved
—