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Edge Port Module (EPORT)
18-4
Freescale Semiconductor
18.4.2
EPORT Data Direction Register (EPDDR)
The EPORT data direction register (EPDDR) controls the direction of each one of the pins individually.
Table 18-3. EPPAR Field Descriptions
Field
Description
15–0
EPPA
n
EPORT pin assignment select fields. The read/write EPPA
n
fields configure EPORT pins for level detection and rising
and/or falling edge detection.
Pins configured as level-sensitive are active-low (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 IRQ
n
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 EPPA
n
fields.
00 Pin IRQ
n
level-sensitive
01 Pin IRQ
n
rising edge triggered
10 Pin IRQ
n
falling edge triggered
11 Pin IRQ
n
falling edge and rising edge triggered
Address: 0xFC09_4002 (EPDDR)
Access: Supervisor read/write
7
6
5
4
3
2
1
0
R
EPDD7
EPDD6
EPDD5
EPDD4
EPDD3
EPDD2
EPDD1
EPDD0
W
Reset
0
0
0
0
0
0
0
0
Figure 18-3. EPORT Data Direction Register (EPDDR)
Table 18-4. EPDDR Field Descriptions
Field
Description
7–0
EPDD
n
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–EPDD0.
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
Summary of Contents for MCF54455
Page 33: ...xxviii Freescale Semiconductor ...
Page 67: ...Freescale Semiconductor 1 ...
Page 125: ...Freescale Semiconductor 1 ...
Page 145: ...Enhanced Multiply Accumulate Unit EMAC 5 21 Freescale Semiconductor ...
Page 173: ...Cache 6 28 Freescale Semiconductor ...
Page 179: ...Static RAM SRAM 7 6 Freescale Semiconductor ...
Page 207: ...Power Management 9 16 Freescale Semiconductor ...
Page 323: ...Reset Controller Module 13 8 Freescale Semiconductor ...
Page 389: ...Pin Multiplexing and Control 16 44 Freescale Semiconductor ...
Page 575: ...PCI Bus Controller 22 58 Freescale Semiconductor ...
Page 600: ...Advanced Technology Attachment ATA Freescale Semiconductor 23 25 ...
Page 601: ...Freescale Semiconductor 1 ...
Page 842: ...I2 C Interface Freescale Semiconductor 33 16 ...
Page 843: ...Freescale Semiconductor 1 ...
Page 921: ...Revision History A 6 Freescale Semiconductor ...