Low-Voltage Inhibit (LVI)
LVI Interrupts
MC68HC908MR16/MC68HC908MR32 — Rev. 4.0 Advance Information
MOTOROLA Low-Voltage Inhibit (LVI) 339
TRPSEL — LVI Trip Select Bit
This bit selects the LVI trip point. Reset clears this bit.
1 = 5 percent tolerance. The trip point and recovery point are
determined by VLVR1 and VLVH1, respectively.
0 = 10 percent tolerance. The trip point a nd recovery point are
determined by VLVR2 and VLVH2, respectively.
NOTE: If LVIRST and LVIPWR are at logic 0, note that when changing the
tolerence, LVI reset will be generated if the supply voltage is below the
trip point.
18.6 LVI Interrupts
The LVI module does not generate interrupt requests.
18.7 Wait Mode
The WAIT instruction puts the MCU in low power- co nsu mp ti on stan dby
mode.
With the LVIPWR bit in the configuration register programmed to lo gic 1,
the LVI module is active after a WAIT instruction.
With the LVIRST bit in the configuration r egister p rogrammed to log ic 1,
the LVI module can generate a reset and bring the MCU out of wait
mode.
Table 18-1. LVIOUT Bit Indication
VDD LVIOUT
At Level: For Number of
CGMXCLK Cycles:
VDD > VLVRX + VLVHX Any 0
VDD < VLVRX < 32 CGMXCLK cycles 0
VDD < VLVRX Between 32 & 40 CGMXCLK cycles 0 or 1
VDD < VLVRX > 40 CGMXCLK cycles 1
VLVRX < VDD < VLVRX + VLVHX Any Previous
value