82C836 Datasheet, PDF (59/205 Pages) List of Unclassifed Manufacturers – Single-Chip 386sx AT

s Keyboard Controller Interface ----External 8042
System Interface
Keyboard Controller Interface----External 8042
The 82C836 relies on an external 8042 to handle keyboard operations (see Figure 5-5).
The clock for the 8042 may be derived from BUSCLK or OSC and should have a
frequency between 6MHz and 10MHz when used with standard keyboard controllers.
The 8042 interfaces with the 82C836 through IRQ1 and a chip select line. The 8042
also provides two output signals: GATEA20 and -RESET2. These signals are brought
into the 82C836 and combined internally with the Fast GATE A20 and Fast CPU Reset
functions available via port 92H. The keyboard controller also supports the keylock and
CGA strap functions.
Figure 5-5. Keyboard Controller
5-1 8 Revision 3.0
PRELIMINARY
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