RA8806
Preliminary Version 1.0
Two Layers Character/Graphic LCD Controller
6-5 Key-Scan
RA8806 features with Key-Scan circuit, and could be used as Keyboard function. It will help to integrate
the system circuit that includes keyboard application. The below Figure 6-22 shows the basic application
circuit of 8x8 Key-Pad. RA8806 already built-in pull-up resistors in the pins “KIN[7:0]”.
RA8806
KIN0
KIN1
KIN2
KIN3
KIN4
KIN5
KIN6
KIN7
KOUT0
KOUT1
KOUT2
KOUT3
KOUT4
KOUT5
KOUT6
KOUT7
Figure 6-22 : 8x8 Key-Pad Application
The related Registers of Key-san function are KSCR, KSDR, and KSER. The RA8806 Key-Scan
controller features are given below:
1. Support with 4x8 or 8x8 Key-Scan Matrix
2. Programmable setting of sampling times and scan frequency of Key-Scan
3. Adjustable long key-press Timing
4. Multi-Key is available ( maximum three keys at the same time)
5. Allows the function of “ Key press to wake-up the system”
Table 6-14 is the key code of mapping to key-pad matrix for normal press. The key code will be stored in
REG[A2h] when key was pressed. If it was a long time press, then the key code is show as Table 6-15.
Table 6-14 : Key Number Mapping Table (Normal Key)
ROW #
0
1
2
3
4
5
6
7
0
1
2
3
4
5
6
7
00h 01h 02h 03h 04h 05h 06h 07h
10h 11h 12h 13h 14h 15h 16h 17h
20h 21h 22h 23h 24h 25h 26h 27h
30h 31h 32h 33h 34h 35h 36h 37h
40h 41h 42h 43h 44h 45h 46h 47h
50h 51h 52h 53h 54h 55h 56h 57h
60h 61h 62h 63h 64h 65h 66h 67h
70h 71h 72h 73h 74h 75h 76h 77h
COL #
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