Sharp FO-CC500 Service Manual page 65

3) Controller Peripheral Functions
Several peripheral phone functions are supported via the
microcontroller registers or dedicated hardware.
General purpose timers are configured to provide the timing required
for firmware execution. An asynchronous serial port and a dedicated
Codec serial port are also available. GPIOs are provided for periph-
eral control. Several GPIOs are dedicated to interface to peripherals
such as the LEDs, keypad, RF control, and serial EEPROM control.
GPIOs are also used as dedicated interfaces for phone functions such
as ring detection and hook relay control.
General Purpose Timer A. Timer A is used for various firmware needs
such as link timing. It generates either single or continuous interrupts
and consists of an 8-bit interval register (TmrA) for the interval value,
an 8-bit counter for generating the timer interrupt, and a divide-by-
256 prescaler. Timer A uses the main 9.6 MHz clock divided by 256.
General Purpose Timer B. Timer B may be configured as a general
purpose timer or as an ART serial port. When configured as a timer,
its operation is similar to that of Timer A.
Timer B consists of an 8-bit interval register (TmrB), a divide-by-5
prescaler and an 8-bit counter. Timer B uses the main 9.6 MHz clock
divided by 5.
Asynchronous Receiver/Transmitter. An asynchronous serial port
with a programmable baud rate can be configured using Timer B. The
ART logic controls the two-pin asynchronous serial port of the ASIC.
The ART port is used for base/handset data transfer and as the test
interface.
ITAD
D7 D6 D5 D4 D3 D2 D1 D0
PWR
R/W
RS
E
DB7
DB6
DB5
DB4
DB3
DB2
DB1
DB0
D7 D6 D5 D4 D3 D2 D1 D0
keypad
switches
Fig. 10 Keypad/Switch/LCD/ITAD Interface
Keypad/Switch/LCD/ITAD/Seven Segment Interface. This interface
is used to provide multiplexed control for a 6x8 keypad, up to eight
switches, and a parallel interface for an LCD (see Fig. 10). For a
keypad interface, the eight KEYPADR[7:0] control signals are driven
low, one at a time, and the six KEYPADC[5:0] inputs, with internal
pullup resistors, are read to determine which key in the 48-key matrix
is closed. The firmware scans the keypad at 10 ms intervals and
debounces the key presses.
LCDPWR
LCDRW
LCDRS
LCDEN
keypadR7
keypadR6
keypadR5
keypadR4
keypadR3
keypadR2
keypadR1
keypadR0 key
press
wakeup
&
status
keypadC5
flag
keypadC4
keypadC3
keypadC2
keypadC1
keypadC0
Diodes D7-D0 are
required for isolation
if KEYPADC pins are
used to also drive LCD
or switches.
SWCTL/GPIOC0
5 – 15
For a switch interface, the eight KEYPADR[7:0] control signals are
driven, one at a time, and GPIOC0, with an internal pullup resistor, is
read to determine if a switch is open or closed.
KEYPADC0 is used to select either 900 MHz or 2.4 GHz control.
Not connecting KEYPADC0 and SWCTL (GPIOC0) selects 900 MHz
radio control. A diode connected between KEYPADC0 and SWCTL
(GPIOC0) selects 2.4 GHz radio control.
An LCD interface can be implemented as shown in Fig. 10.
Keypad signals are used for the LCD data interface and GPIOs are
used for the LCD control lines. The LCD driver and LCD management
software must be written by the OEM.
An ITAD interface can be implemented by multiplexing KEYPADR[7:0]
as ITAD data lines and using GPIOs as ITAD control lines.
A seven-segment interface can be implemented by multiplexing
KEYPADR[7:0] as data lines and GPIOs as control lines to switch
between different bank of LEDs.
Codec Serial Port. Digitized voice-band audio is supported through
an interrupt-driven, 5-pin serial Codec interface. Clock and frame tim-
ing for the Codec are internally generated and externally output to the
device. The Codec serial port interfaces to the Merlin Codec. The
Codec serial port uses three memory-mapped locations to interface
with the controller. They consist of high and low Codec data bytes,
which are used to write out 16 bits of Tx data and read 16 bits of Rx
data, and an 8-bit Codec configuration/status register.
The ASIC can interface with up to two Codecs by sharing the clock
and control signals between the two Codecs, and by using GPIOs as
the serial data input and output for the second Codec.
RF Transceiver Control. The ASIC allocates several GPIOs to con-
trol all necessary radio transceiver functions. Two pins control the
Power Amplifier (PA) output levels. Four pins make up the synthe-
sizer serial port, clock data, strobe, and synthesizer enable. One pin
is used as the LNA attenuation control and two pins are used for TR
switch control and Tx/Rx enable. The OEM can select ASIC support
for either the 900 MHz or 2.4 GHz radio.
The firmware protocol for programming the Conexant synthesizer in
the RF105 and RF109 and the radio link parameter settings are auto-
matically configured with the selection of the 900 MHz or 2.4 GHz
radio. The OEM can select the radio type using the keypad switch
control, or by the OEM configuration settings in serial EEPROM or
external ROM. If the radio type is selected using serial EEPROM or
external ROM, the keypad switch control radio selection is not used.
Battery Detector. This analog function performs A/D conversion on
the battery voltage and makes it available to the microcontroller for
battery quality estimation. External level shifting resistors set the in-
put level to the ASIC. The low battery threshold can be set by the
OEM in EEPROM.
Two multiplexed inputs are available to monitor more than one volt-
age supply level.
General Purpose Inputs/Outputs (GPIOs). GPIOs are available on
all Merlin ASICs. GPIOs are software bit-configurable as inputs or
outputs. The GPIOs may be used as dedicated control signals for
LED drivers, LCD control, hook relay control, ring detection, RF con-
trol, half-duplex speakerphone device control, serial EEPROM inter-
face, ITAD device control, and seven-segment LED control, depend-
ing on the system configuration. The recommended GPIO assign-
ments.
Ringer/Buzzer Control. A ringer/buzzer can be driven by either the
Codec LINEO, the ASIC AUXDAC, or a GPIO.
FO-CC500A
FO-K01A