External Signal Descriptions - Freescale Semiconductor MCF54455 Reference Manual

Chip Configuration Module (CCM)
11.2

External Signal Descriptions

Table 11-1 provides an overview of the CCM signals.
Name
BOOTMOD[1:0]
FB_AD[7:0]
11.2.1 BOOTMOD[1:0]
If the BOOTMOD[1:0] signals determine the boot performed at reset. See the table below for
BOOTMOD[1:0] usage.
BOOTMOD[1:0]
00
01
10
11
11.2.2 FB_AD[7:0] (Reset Configuration Override)
If the external BOOTMOD[1:0] pins are driven to 10 during reset, the states of the FB_AD[7:0] pins
during reset determine Flexbus, PCI, and PLL configurations after reset.
The logic levels for reset configuration on FB_AD[7:0] must be actively
driven when BOOTMOD equals 10. FB_AD[31:8] should be allowed to
float or be pulled high.
11.3 Memory Map/Register Definition
The CCM programming model consists of the registers listed in the below table.
Address
0xFC0A_0004 Chip Configuration Register (CCR)
0xFC0A_0008 Reset Configuration Register (RCON)
0xFC0A_000A Chip Identification Register (CIR)
11-2
Table 11-1. Signal Properties
Function
Reset configuration select
Reset configuration override pins
Table 11-2. BOOTMOD[1:0] Values
Boot from Flexbus with defaults.
Reserved.
Boot from Flexbus and override defaults via data bus (FB_AD[7:0]).
Boot from Flexbus and override defaults via the serial boot facility (SPI
EEPROM/flash). See Chapter 12, "Serial Boot Facility (SBF)."
NOTE
Table 11-3. CCM Memory Map
Register
Supervisor Access Only Registers
Reset State
—
—
Meaning
Width
Access Reset Value
(bits)
1
16 R See Section
16 R 0x03ED_0346
16 R See Section
Section/Page
11.3.1/11-3
11.3.2/11-7
11.3.3/11-8
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