HL15604
When any one of these keys is pressed, the
oscillator on the OSC pin is started and the keys
are scanned.
“ L” KS1
“ L” KS2
“ L” KS3
“ L” KS4
“ L” KS5
“ H” KS6
*)
KIN1
KIN2
KIN3
KIN4
KIN5
*) These diodes are required to reliable recognize multiple key presses on the KS6 line when sleep mode state with only
KS6 high, as in the above example. That is, these diodes prevent incorrect operation due to sneak currents in the KS6
key scan output signal when keys on the KS1 to KS5 lines are pressed at the same time.
Key input
(KS6 line)
Key Scan
800T
800T
CE
Write
address
Write
address
Read
address
Write
address
Read
address
SI
SO
Key data read
Key data read
Key data read request
Key data read request
Multiple Key Presses
Although the HL14104 is capable of key scanning without inserting diodes for
dual key presses, triple key presses on the KIN1 to KIN5 input pin lines, or mult-
iple key presses on the KS1 to KS6 output pin lines, multiple presses other than
these cases may result in keys that were not pressed recognized as having been
pressed. Therefore, a diode must be inserted in series with each key. Application
that do not recognize multiple key presses of threes or keys should check the key
data for three or more 1 bits and ignore such data.
15
HYNIX [ HYNIX SEMICONDUCTOR ]
