
Edge Port Module (EPORT)
MCF5271 Reference Manual, Rev. 2
15-4
Freescale Semiconductor
15.4.1.2 EPORT Data Direction Register (EPDDR)
Table 15-3. EPPAR Field Descriptions
Bits
Name
Description
15–2
EPPAn
EPORT pin assignment select fields. The read/write EPPAn fields configure EPORT pins
for level detection and rising and/or falling edge detection.
Pins configured as level-sensitive are inverted so that a logic 0 on the external pin
represents a valid interrupt request. Level-sensitive interrupt inputs are not latched. To
guarantee that a level-sensitive interrupt request is acknowledged, the interrupt source
must keep the signal asserted until acknowledged by software. Level sensitivity must be
selected to bring the device out of stop mode with an IRQn interrupt.
Pins configured as edge-triggered are latched and need not remain asserted for interrupt
generation. A pin configured for edge detection can trigger an interrupt regardless of its
configuration as input or output.
Interrupt requests generated in the EPORT module can be masked by the interrupt
controller module. EPPAR functionality is independent of the selected pin direction.
Reset clears the EPPAn fields.
00 Pin IRQn level-sensitive
01 Pin IRQn rising edge triggered
10 Pin IRQn falling edge triggered
11 Pin IRQn both falling edge and rising edge triggered
1–0
—
Reserved, should be cleared.
15
14
13
12
11
10
987
6543210
R
EPDD7
EPDD6
EPDD5
EPDD4
EPDD3
EPDD2
EPDD1
0
W
Reset
0000000000000000
Address
IPSBAR + 0x13_0002
Figure 15-3. EPORT Data Direction Register (EPDDR)
Table 15-4. EPDD Field Descriptions
Bits
Name
Description
7–1
EPDDn
Setting any bit in the EPDDR configures the corresponding pin as an output. Clearing any
bit in EPDDR configures the corresponding pin as an input. Pin direction is independent of
the level/edge detection configuration. Reset clears EPDD7–EPDD1.
To use an EPORT pin as an external interrupt request source, its corresponding bit in
EPDDR must be clear. Software can generate interrupt requests by programming the
EPORT data register when the EPDDR selects output.
0 Corresponding EPORT pin configured as input
1 Corresponding EPORT pin configured as output
0
—
Reserved, should be cleared.