
Operating Modes and On-Chip Memory
Memory Map
MC68HC11E Family
—
Rev. 4
Technical Data
MOTOROLA
Operating Modes and On-Chip Memory
91
4.4.3.3 System Configuration Options Register
The 8-bit, special-purpose system configuration options register
(OPTION) sets internal system configuration options during initialization.
The time protected control bits, IRQE, DLY, and CR[1:0], can be written
only once after a reset and then they become read-only. This minimizes
the possibility of any accidental changes to the system configuration.
ADPU
—
Analog-to-Digital Converter Power-Up Bit
Refer to
Section 10. Analog-to-Digital (A/D) Converter
.
CSEL
—
Clock Select Bit
Selects alternate clock source for on-chip EEPROM charge pump.
Refer to
4.6.1 EEPROM and CONFIG Programming and Erasure
for more information on EEPROM use.
CSEL also selects the clock source for the A/D converter, a function
discussed in
Section 10. Analog-to-Digital (A/D) Converter
.
IRQE
—
Configure IRQ for Edge-Sensitive Only Operation Bit
Refer to
Section 5. Resets and Interrupts
.
DLY
—
Enable Oscillator Startup Delay Bit
0 = The oscillator startup delay coming out of stop mode is
bypassed and the MCU resumes processing within about four
bus cycles.
1 = A delay of approximately 4000 E-clock cycles is imposed as the
MCU is started up from the stop power-saving mode. This
delay allows the crystal oscillator to stabilize.
Address:
$1039
Bit 7
6
5
4
3
2
1
Bit 0
Read:
ADPU
CSEL
IRQE
(1)
DLY
(1)
CME
CR1
(1)
CR0
(1)
Write:
Reset:
0
0
0
1
0
0
0
0
1. Can be written only once in first 64 cycles out of reset in normal modes or at any time during
special modes.
= Unimplemented
Figure 4-13. System Configuration Options Register (OPTION)