Motorola MCF5281 用户手册
MOTOROLA
Chapter 30. Chip Configuration Module (CCM)
30-9
Functional Description
If the RCON pin is not asserted during reset, the chip configuration and the reset
configuration pin functions after reset are determined by RCON or fixed defaults,
regardless of the states of the external data pins. The internal configuration signals are
driven to levels specified by the RCON register’s reset state for default module
configuration.
configuration pin functions after reset are determined by RCON or fixed defaults,
regardless of the states of the external data pins. The internal configuration signals are
driven to levels specified by the RCON register’s reset state for default module
configuration.
If the RCON pin is asserted during reset, then various chip functions, including the reset
configuration pin functions after reset, are configured according to the levels driven onto
the external data pins. (See Table 30-10) The internal configuration signals are driven to
reflect the levels on the external configuration pins to allow for module configuration.
configuration pin functions after reset, are configured according to the levels driven onto
the external data pins. (See Table 30-10) The internal configuration signals are driven to
reflect the levels on the external configuration pins to allow for module configuration.
Table 30-9. Reset Configuration Pin States During Reset
Pin
Pin
Function
1
1
If the external RCON pin is not asserted during reset, pin functions are determined by the default
operation mode defined in the RCON register. If the external RCON pin is asserted, pin functions are
determined by the override values driven on the external data bus pins.
operation mode defined in the RCON register. If the external RCON pin is asserted, pin functions are
determined by the override values driven on the external data bus pins.
I/O
Output
State
Input
State
D[26:24, 21, 19:16],
PA[2:0], PB[5, 3:0]
PA[2:0], PB[5, 3:0]
Digital I/O or primary
function
function
Input
—
Must be driven
by external logic
by external logic
RCON
RCON function for all
modes
modes
2
2
During reset, the external RCON pin assumes its RCON pin function, but this pin changes to the
function defined by the chip operation mode immediately after reset. See Table 30-10.
function defined by the chip operation mode immediately after reset. See Table 30-10.
Input
—
Internal weak pull-up
device
device
CLKMOD1, CLKMOD0
Not affected
Input
—
Must be driven by
external logic
external logic
Table 30-10. Configuration During Reset
1
Pin(s) Affected
Default
Configuration
Override Pins
in Reset
2, 3 4
Function
D[31:0], R/W, TA, TEA,
TSIZ[1:0], TS, TIP, OE, A[23:0],
BS[3:0], CS[3:0]
RCON0 = 0
D[26,17:16]
Chip Mode Selected
111
Master mode
110
Single-chip mode
5
100 or 0XX
Reserved
CS0
RCON[4:3] = 00
RCON2 = 0
D[19:18]
Boot Device
00
Internal with 32-bit port
5
10
External with 8-bit port
01
External with 16-bit port
11
External with 32-bit port
All output pins
RCON5 = 1
D21
Output Pad Drive Strength
0
Partial strength
1
Full strength
5