ht82k68a Holtek Semiconductor Inc., ht82k68a Datasheet - Page 16

• Manufacturer Part Number: ht82k68a
• Description: Ht82k68a -- Multimedia Keyboard Encoder 8-bit Mask Mcu
• Manufacturer: Holtek Semiconductor Inc.

Mask Option
The following shows five kinds of mask option in the HT82K68A. All the mask options must be defined to ensure proper
system function.
Application Circuits
Rev. 1.70
No.
1
2
3
4
5
6
7
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 activated, otherwise the XST is dis-
abled.
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. One time means
that the CLR WDT instruction can clear the WDT. Two times means only if both of the CLR WDT1 and
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.
LVR enable/disable. User can configure whether enable or disable the circuit by configuration option.
Input type selection. The input type can select inverter or Schmitt by mask option (for OTP version, only
Schmitt input type can used)
CLR WDT2 instructions have been executed, only then will the WDT be cleared.
Mask Option
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December 26, 2005
HT82K68A