System Integration Unit (SIU)
MPC5566 Microcontroller Reference Manual, Rev. 2
Freescale Semiconductor 6-5
6.2.1.2 Reset Output (RSTOUT)
RSTOUT is an active-low output signal that uses a push/pull configuration. It is driven to the low state by
the MCU for all internal and external reset sources. After the RESET input signal negates, RSTOUT
asserts for:
• 16000 clock cycles for devices configured in bypass mode
• 16004 clock cycles for devices configured for FMPLL dual-controller mode (1:1)
• 2404 clock cycles for all other FMPLL modes
To invoke an external software reset, write a 1 to the system external reset (SER) bit in the system reset
control register (SIU_SRCR). This asserts RSTOUT for 2400 clock cycles. An external software reset
does not execute the BAM module or sample BOOTCFG[0:1].
6.2.1.3 General-Purpose I/O (GPIO[0:213])
The GPIO signals provide general-purpose input and output functions. GPIO signals are generally
multiplexed with other I/O pin functions. Each GPIO input and output is separately controlled by an
eight-bit general-purpose data input (SIU_GPDIn) and a general-purpose data output (SIU_GPDOn)
register.
Refer to the following sections for more information:
Section 6.3.1.159, “GPIO Pin Data Output Registers 0–213 (SIU_GPDOn)”
Section 6.3.1.160, “GPIO Pin Data Input Registers 0–213 (SIU_GPDIn)”
6.2.1.4 Boot Configuration (BOOTCFG[0:1])
The BOOTCFG value specifies the location and boot mode used by the boot assist module (BAM). All
reset sources can read the boot configuration field, BOOTCFG[0:1], except a debug port reset and a
software external reset.
The BOOTCFG values are read only if RSTCFG asserts while RSTOUT is asserted. The BOOTCFG
signal asserts after RSTCFG to get the boot input information. BOOTCFG[0:1] is sampled four clock
cycles before RSTOUT
negates, and the latched boot values are stored in the reset status register
(SIU_RSR).
If RSTCFG asserts while processing a reset, BOOTCFG[0:1] is sampled. Otherwise, if RSTCFG negates
while processing a reset, the following occurs:
1. BOOTCFG[0:1] is not sampled
2. BAM module boots from internal flash (default = 0b00)
3. Boot value from internal flash is written to BOOTCFG[0:1] field in the reset status register
(SIU_RSR)
4. BOOTCFG[0:1] values are latched and driven as output signals from the SIU
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