Canon AS-100M, Field Service Manual

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8401 processor Is used for key code generation control and
has a 1KB ROM incorporated to control the timing of key code
generation, selected key code designation, and serial output.
The key matrix comprises of 13 sampling timings, KSO 'v KS12 and
key code KDO 'V KD7 of
8
bits, thus, 13 x
8
» 104 different keys
can be discriminated. Pointing device is connected onto key
matrix with eight keys of 104 appropriated for pointing device.
Concept of key code generation
Key -
pressing
Sampling
Confirmation of key release
when key code is same as
( D , key data IB
8
th
bit is "
0
" are serially
transferred.
©
n _
I
Confirmation of key release
when key code is same
as (3) , key data IB
8
th
bit is is "l" are _
serially transferred.
Key data are generated respectively when a key is pressed and
released, then, serially transferred to key input circuit.
CPU converts key data into internal codes. When key release time
exceeds 640ms, CPU automatically generates an internal code con­
tinuously as repeat mode.
KEY BOARD option
Pointing device ...... Carsol control for graphic.
1.2.5 5" FDD
The 5" FDD has two built-in MDD-220 units and is connected to
I/O controller via FDD controller, using a star chain.
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