HL15604
Key input 1
Key input 2
Key Scan
800T
800T
800T
CE
Write
address
Write
address
Read
address
Write
address
Read
address
Read
address
SI
SO
Key data read
Key data read
Key data read request
Key data read
Key data read request
Key data read request
3) In sleep mode
• The pins KS1 to KS6 are set to high or low by the S0 and S1 bits in the
sleep mode control register.
• If a key on one of the lines corresponding to a KS1 to KS6 pin which is set
high is pressed, the oscillator on the OSC pin is started and a key scan is
performed. Keys are scanned until all keys are released. Multiple key pre-
sses are recognized by determining whether multiple key data bits are set.
• If a key is pressed for longer than 800T ( where T=1/fosc ) the HL14104
outputs a key data read request (a low level on SO) to the controller. The
controller acknowledges this request and reads the key data. However, if
CE is high during a serial data transfer, SO will be set high.
• After the controller reads the key data, the key data read request is cleared
( SO is set high ) and the HL14104 performs another key scan. However
this does not clear sleep mode. Also note that SO, being an open-drain
output, requires a pull-up resistor ( between 1 and 10 K).
• Sleep mode key scan example
Example : S0 = 0, S1 = 1 ( sleep with only KS6 high )
14
HYNIX [ HYNIX SEMICONDUCTOR ]
