MOTOROLA
MC68349 USER'S MANUAL
4- 33
SLOCK—Synthesizer Lock
1 = VCO has locked onto the desired frequency (or system clock is driven externally).
0 = VCO is enabled, but has not yet locked.
RSTEN—Reset Enable
1 = Loss of input signal causes a system reset.
0 = Loss of input signal causes the VCO to operate at a nominal speed without
external reference (limp mode), and the device continues to operate at that
speed.
STSIM—Stop Mode System Integration Clock
1 = When LPSTOP is executed, the SIM49 clock is driven from the VCO.
0 = When LPSTOP is executed, the SIM49 clock is driven from an external crystal or
oscillator, and the VCO is turned off to conserve power.
STEXT—Stop Mode External Clock
1 = When the LPSTOP instruction is executed, the external clock pin (CLKOUT) is
driven from the SIM49 clock as determined by the STSIM bit.
0 = When the LPSTOP instruction is executed, the external clock (CLKOUT) is held
low to conserve power. No external clock will be driven in LPSTOP mode.
4.3.4 Chip Select Registers
The following paragraphs provide descriptions of the registers in the chip select function,
and an example of how to program the registers. The chip select registers cannot be
accessed until the register is initialized.
4.3.4.1 BASE ADDRESS REGISTERS. There are four 32-bit base address registers in
the chip select function, one for each chip select signal.
Base Address
$044 (CS0), $04C (CS1), $054 (CS2), $05C (CS3)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
BA31
BA30
BA29
BA28
BA27
BA26
BA25
BA24
BA23
BA22
BA21
BA20
BA19
BA18
BA17
BA16
RESET:
UUUUUUUUUUUUUUUU
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
BA15
BA14
BA13
BA12
BA11
BA10
BA9
BA8
BFC3
BFC2
BFC1
BFC0
WP
EDS
NCS
V
RESET:
UUUUUUUUUUUUUU0
0
U = Unaffected by reset
Supervisor Only
BA31–BA8—Base Address Bits 31–8
The base address field, the upper 24 bits of each base address register, selects the
starting address for the chip select. The specified base address must be on a multiple of
the selected block size. The corresponding bits, AM31–AM8, in the address mask