System Integration Unit (SIU)
MPC5566 Microcontroller Reference Manual, Rev. 2
6-4 Freescale Semiconductor
 
6.2 External Signal Description
Table 6-3 lists the external pins used by the SIU. 
6.2.1 Detailed Signal Descriptions
6.2.1.1 Reset Input (RESET)
RESET is an active-low input signal asserted by an external device during a power-on reset (POR) or 
external reset. If RESET asserts for ten clock cycles only, the internal reset signal asserts. Asserting the 
RESET
 signal while the device is processing a reset restarts the reset process at the beginning. 
RESET has a glitch detector logic that senses electrical fluctuations on the V
DDEH
 input pins that drop 
below the switch point value for more than two clock cycles. The switch point value is between the 
maximum V
IL
 and minimum V
IH
 specifications for the V
DDEH
 input pins. 
Table 6-3. SIU Signal Properties
Name Function
I/O
Type
Pad
Type
Pullup
Pulldown 
1
1
Internal weak pullup/down. The reset weak pullup/down state for the primary signal function is given. For example, the reset 
weak pullup/down state of the BOOTCFG[0:1]_GPIO[211:212] signal is weak pulldown enabled.
Resets
RESET Reset input Input — Up
RSTOUT Reset output Output Slow —
System Configuration 
GPIO[0:210] General-purpose I/O I/O Slow Up/down
BOOTCFG[0:1]_
GPIO[211:212]
Boot configuration input 
General-purpose I/O
Input
I/O
Slow Down
Up/down
WKPCFG_
GPIO[213]
Weak-pull configuration 
General-purpose I/O
Input
I/O
Slow Up
Up/down
External Interrupt 
IRQ[0:15] 
2
2
The GPIO and IRQ signals are multiplexed with other functions on the device.
External interrupt request input Input Slow —
3
3
The weak pullup/down state at reset for the IRQ signals depends on the muxed signals that share the pin. The weak 
pullup/down state for these pins is as follows:
IRQ
[0, 1, 4, 5, 6, 7, 12:14]Up 
IRQ
[2, 3, 15] Down 
IRQ[8:11] WKPCFG