HT82K68 Holtek Semiconductor Inc, HT82K68 Datasheet - Page 19
HT82K68
Manufacturer Part Number
HT82K68
Description
Multimedia Keyboard Encoder OTP
Manufacturer
Holtek Semiconductor Inc
Datasheet
1.HT82K68.pdf
(40 pages)
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ROM code option
The following shows six kinds of ROM code option in the HT82K68E. All the ROM code options must
be defined to ensure proper system function.
No.
1
2
3
4
5
6
OSC type selection. This option is to decide if an RC or Crystal oscillator is chosen as system
clock. If the Crystal oscillator is selected, the XST (Crystal Start-up Timer) default is acti-
vated, otherwise the XST is disabled.
WDT source selection. There are three types of selection: on-chip RC oscillator, instruction
clock or disable the WDT.
CLRWDT times selection. This option defines the way to clear the WDT by instruction. ²One
time² means that the CLR WDT instruction can clear the WDT. ²Two times² means only if
both of the CLR WDT1 and CLR WDT2 instructions have been executed, only then will the
WDT be cleared.
Wake-up selection. This option defines the wake-up function activity. External I/O pins (PA
and PC [0:3] only) all have the capability to wake-up the chip from a HALT.
Pull-high selection. This option is to decide whether the pull-high resistance is visible or not
in the input mode of the I/O ports. Each bit of an I/O port can be independently selected.
Special power on reset. This option defines the function will reset the chip to prevent incor-
rect status.
If the special power on reset is enabled, the chip must not enter the HALT mode.
Preliminary
ROM Code Option
19
HT82K68E
August 8, 2000