STFPC311

3 Initialization

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3

Initialization

After the power is plugged in, the device will supply power to all of the components (including

the host processor) by setting STBY to logic low in order to allow the host processor to program

the STFPC311. Once the STBY is set to low, the watchdog timer starts to count up to 10s (10s

is the default value of the watchdog timer upon power-up). When the READY is asserted within

this time, it indicates that the system has booted up well. If the READY pin is not asserted (logic

high) within this time (10s), the STFPC311 will put the system into standby mode again by

setting STBY to logic high.

If READY is detected as logic high, the watchdog timer will be turned OFF. The main processor

should program the remote control hot key and initialize the other parameters of the STFPC311

in preparation for normal operation before the system goes into standby mode. After all of the

STFPC311 configuration is finished, the host processor may set the READY to low so that the

STFPC311 enters standby mode. The STFPC311 then sets the MUTE pin to logic high to mute

the audio output as well as the STBY pin to logic high. As a consequence of this action, the

main supply voltage is turned off.

3.1

Normal mode of operation

After the power is plugged in, the device will supply power to all of the components (including

the host processor) by setting STBY to logic low in order to allow the host processor to program

the STFPC311. Once the STBY is set to low, the watchdog timer starts to count up to 10s (10s

is the default value of the watchdog timer upon power-up). When the READY is asserted within

this time, it indicates that the system has booted up well. If the READY pin is not asserted (logic

high) within this time (10s), the STFPC311 will put the system into standby mode again by

setting STBY to logic high.

If READY is detected as logic high, the watchdog timer will be turned OFF. The main processor

should program the remote control hot key and initialize the other parameters of the STFPC311

in preparation for normal operation before the system goes into standby mode. After all of the

STFPC311 configuration is finished, the host processor may set the READY to low so that the

STFPC311 enters standby mode. The STFPC311 then sets the MUTE pin to logic high to mute

the audio output as well as the STBY pin to logic high. As a consequence of this action, the

main supply voltage is turned off.

3.2

Receive operation

In receive condition, the STFPC311 waits for a valid command from the MCU. The receive

circuit of STFPC311 receives 8 bit serial data, latches the data and then masks the inputs from

3.3

Transmit operation

In transmit condition, the STFPC311 sends the 8-bit serial data (LSB transmitted first)

whenever a key is pressed or IR data is received. STFPC311 transmits data on the falling edge

of CLK. Refer to Figure 29 on page 32 for transmit timing.