Datasheet

Chapter 6 Parallel Input/Output Control
MC9RS08KA2 Series Data Sheet, Rev. 4
48 Freescale Semiconductor
corresponding pulling device enable register bit. The pulling device is also disabled if the pin is controlled
by an analog function.
6.3.1.2 Pullup/Pulldown Control
Pullup/pulldown control is used to select the pullup or pulldown device enabled by the corresponding
PTAPE bit.
Figure 6-5. Pullup/Pulldown Device Control for Port A (PTAPUD)
6.3.1.3 Output Slew Rate Control Enable
Slew rate control can be enabled for each port pin by setting the corresponding bit in the slew rate control
register (PTASEn). When enabled, slew control limits the rate at which an output can transition in order to
reduce EMC emissions. Slew rate control has no effect on pins that are configured as inputs.
76543210
R
00
PTAPE5 PTAPE4
0
PTAPE2 PTAPE1 PTAPE0
W
Reset:00000000
Figure 6-4. Internal Pulling Device Enable for Port A Register (PTAPE)
Table 6-3. PTAPE Register Field Descriptions
Field Description
5:4,2:0
PTAPE[5:4,2:0]
Internal Pulling Device Enable for Port A Bits — Each of these control bits determines whether the internal
pulling 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 pulling device disabled for port A bit n.
1 Internal pulling device enabled for port A bit n.
76543210
R
00
PTAPUD5 PTAPUD4
0
PTAPUD2 PTAPUD1 PTAPUD0
W
Reset:00000000
Table 6-4. PTAPUD Register Field Descriptions
Field Description
5:4,2:0
PTAPUD[5:4,2:0]
Pullup/Pulldown Device Control for Port A Bits — Each of these control bits determines whether the
internal pullup or pulldown device is selected for the associated PTA pin. The actual pullup/pulldown device
is only enabled by enabling the associated PTAPE bit.
0 Internal pullup device is selected for port A bit n.
1 Internal pulldown device is selected for port A bit n.