Chapter 3: The TI-89 / TI-92 Plus Hardware Overview
11
TI
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89 / TI
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92 Plus Developer Guide
Not for Distribution
Beta Version January 26, 2001
3.3. ASIC registers
When accessing the ASIC registers, it is important to modify only the intended
bits.
0x600000 System Configuration — Detect stack overflow.
876643 2 10
Stack protect
enable.
Table 3.3: System Configuration Register
When Bit 2 is set, logic is enabled that triggers a level 7 interrupt on any write to
addresses 0xE000000 through 0xFFFFFF and 0x000000 through 0x00003FF.
This mechanism is used to detect stack overflow without the penalty of a
software stack probe.
0x600004 System sleep / wake-up — Stop the system oscillator to preserve power.
Specify wake-up condition. Interrupt level
required for wake-up.
8765 4 3210
System
timer
DBus IO Not used Key
interrupt
Heartbeat
timer
Table 3.4: System Sleep Register
Writing to this register will stop the system oscillator. The system oscillator is
restarted by any interrupt whose corresponding bit is set to one. Interrupts level 6
and 7 always restart the oscillator.
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