Datasheet

Register Descriptions
56F8037/56F8027 Data Sheet, Rev. 8
Freescale Semiconductor 111
Figure 6-16 I/O Short Address Location Low Register (SIM_IOSALO)
6.3.14.1 Input/Output Short Address Location (ISAL[21:6])—Bits 15–0
This field represents the lower 16 address bits of the “hard coded” I/O short address.
6.3.15 Protection Register (SIM_PROT)
This register provides write protection of selected control fields for safety-critical applications. The
primary purpose is to prevent unsafe conditions due to the unintentional modification of these fields
between the onset of a code runaway and a reset by the COP watchdog. The GPIO and Internal Peripheral
Select Protection (GIPSP) field protects the contents of registers in the SIM and GPIO modules that control
inter-peripheral signal muxing and GPIO configuration. The Peripheral Clock Enable Protection (PCEP)
field protects the SIM registers’ contents, which contain peripheral clock controls. Some peripherals
provide additional safety features. Refer to the 56F802x and 56F803x Peripheral Reference Manual for
details.
Flexibility is provided so that write protection control values may themselves be optionally locked
(write-protected). Protection controls in this register have two bit values which determine the setting of the
control and whether the value is locked. While a protection control remains unlocked, protection can be
disabled and re-enabled by software. Once a protection control is locked, its value can only be altered by
a chip reset, which restores its default non-locked value.
Figure 6-17 Protection Register (SIM_PROT)
6.3.15.1 Reserved—Bits 15–4
This bit field is reserved. Each bit must be set to 0.
6.3.15.2 Peripheral Clock Enable Protection (PCEP)—Bits 3–2
These bits enable write protection of all fields in the PCEn, SDn, and PCR registers in the SIM module.
• 00 = Write protection off (default)
• 01 = Write protection on
• 10 = Write protection off and locked until chip reset
Base + $11 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
Read
ISAL[21:6]
Write
RESET
1111111 11111 1 1 11
Base + $12 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
Read
0 0 0 0 0 0 0 0 0 0 0 0
PCEP GIPSP
Write
RESET
0000000000000000