ht82m99ee Holtek Semiconductor Inc., ht82m99ee Datasheet - Page 13

• Manufacturer Part Number: ht82m99ee
• Description: Ht82m99ee/ht82m99ae -- Usb Mouse Encoder 8-bit Mcu
• Manufacturer: Holtek Semiconductor Inc.

Reset
There are four ways in which a reset can occur:
The WDT time-out during HALT is different from other
chip reset conditions, since it can perform a warm re -
set that resets only the program counterand SP, leaving
the other circuits in their original state. Some registers
remain unchanged during other reset conditions. Most
registers are reset to the initial condition when the re-
set conditions are met. By examining the PDF and TO
flags, the program can distinguish between different
Note: u stands for unchanged
To guarantee that the system oscillator is started and
stabilized, the SST (System Start-up Timer) provides an
extra delay of 1024 system clock pulses when the sys-
tem resets (power-up, WDT time-out or RES reset) or
the system awakes from the HALT state.
When a system reset occurs, the SST delay is added
during the reset period. Any wake-up from HALT will en-
able the SST delay.
Rev. 1.30
chip resets .
RES reset during normal operation
RES reset during HALT
WDT time-out reset during normal operation
USB reset
TO
0
u
0
1
1
PDF
0
u
0
u
1
RES reset during power-up
RES reset during normal operation
RES wake-up HALT
WDT time-out during normal operation
WDT wake-up HALT
Reset Timing Chart
RESET Conditions
13
The functional unit chip reset status are shown below.
Program Counter
Interrupt
Prescaler
WDT
Timer/event Counter Off
Input/output Ports
Stack Pointer
HT82M99EE/HT82M99AE
Reset Configuration
Reset Circuit
000H
Disable
Clear
Clear. After master reset,
WDT begins counting
Input mode
Points to the top of the stack
August 13, 2007