HD66724 Datasheet, PDF (60/117 Pages) Hitachi Semiconductor – (Graphics LCD Controller/Driver with Key Scan Function)

HD66724/HD66725
Table 35 Key Scan Cycles for Each Operating Frequency
KF1
KF0
Key Scan Pulse Width
Key Scan Cycle
0
0
0.25 ms
1.0 ms (32 clock cycles)
0
1
0.5 ms
2.0 ms (64 clock cycles)
1
0
1.0 ms
4.0 ms (128 clock cycles)
1
1
2.0 ms
8.0 ms (256 clock cycles)
Note: The data is a value obtained when the oscillation frequency (fosc) is 32 kHz. The value depends on
the oscillation frequency.
KST0
Key scan cycle
4.0 ms
1.0 ms
KST1
KST2
KST3
Figure 27 Key Strobe Output Timing (KF1/0 = 10, fcp/fosc = 32 kHz)
Key matrix
Detail
D₃₀ D₂₀ D₁₀ D₀₀
D₃₁ D₂₁ D₁₁ D₀₁
D₃₂ D₂₂ D₁₂ D₀₂
D₃₃ D₂₃ D₁₃ D₀₃
D₃₄ D₂₄ D₁₄ D₀₄
D₃₅ D₂₅ D₁₅ D₀₅
D₃₆ D₂₆ D₁₆ D₀₆
D₃₇ D₂₇ D₁₇ D₀₇
KST0
KST1
KST2
KST3
Key strobe
KIN0
KIN1
KIN2
KIN3
KIN4
KIN5
KIN6
KIN7
Key state fetch
HD66724
HD66725
Figure 28 Key Scan Configuration
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