56F8023_07 datasheet(89/156 Pages) FREESCALE

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56F8023 Data Sheet, Rev. 3

Freescale Semiconductor

Preliminary

Figure 6-15 I/O Short Address Location High Register (SIM_IOSAHI)

6.3.13.1 Reserved—Bits 15—2

This bit field is reserved. Each bit must be set to 0.

6.3.13.2 Input/Output Short Address Location (ISAL[23:22])—Bits 1–0

This field represents the upper two address bits of the “hard coded” I/O short address.

6.3.14 I/O Short Address Location Register Low (SIM_IOSALO)

See Section 6.3.13 for general information about I/O short address location registers.

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.

Base + $10

Read

ISAL[23:22]

Write

RESET

00000

Base + $11

Read

ISAL[21:6]

Write

RESET

11111

56F8023 Datasheet(PDF) 89 Page - Freescale Semiconductor, Inc