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GEMINI
MCUK981201G8
Section 7
Issue A
Technical Guide
– 33 –
Revision 0
7.2.5 General Purpose I/O
The general purpose I/O includes keypad scanning, two PWM ports and 16 general purpose I/O lines. The I/O lines are
multiplexed onto other functions, if I/O is selected the other function is unavailable.
Specific I/O are reserved for the backlight, buzzer and keyboard. The luminosity of the backlight and the loudness of the buzzer
are controlled by a PWM (Pulse Width Modulation) and melody volume control signals.
The PWM are outputs only.
The PWM is clocked at 13/3 MHz.
Tones are generated by using Timer 1 to switch the buzzer PWM on and off at the frequency of Timer 1. By altering the value
of Timer 1, ringing tones can be played.
During hands free operation, the ringing tone is derived from the DSP tone generator.
I/O Pin Assignments
Signal Name
Pin No.
GD90 Function
Description
I/O
WDT_PULSE
High Pulse _/
\_ 500 ns
min.
I/O 1: RXE
116
LOGIC_PWR
H = PSU kept on
L = PSU off
O
I/O 2: TXE
112
nEXT_PWR
L = External Power Supply
H = Battery Power Supply
1
I/O 3: DTR
114
HF_ON
H = Handsfree On
L = Handsfree Off
O
I/O 4: DSR
110
nIGNITION
H = IGNITION Off
L = IGNITION On
I
I/O 5: EXTINT
109
nLVA_INT
Fast non-Maskable Interrupt
N/A
I/O 6: nRESETOUT
106
SIM5Vn3V
H = SIM PWR 5V
L = SIM PWR 3V
O
I/O 7: SIM_RnW
105
ADC_ON
ADC Sample control
H = ADC read enable
L = ADC read disable
O
I/O 8: SIM_PWCTRL
104
SIM_PWRCNT
H = SIM Power Enable
L = SIM Power Disable
O
I/O 9: SIM_CD
95
nON_HOOK
H = Off hook
L = On hook
I
I/O 10: LT
134
BKLT (LED output)
Backlight On
Backlight Off
O
I/O 11: ARMCLK32
73
nHF_SENSE
H = No Hands Free
L = Hands Free connected
I
I/O 12: TSPACT(0)
65
TSPACT(0)
BENA
N/A
I/O 13: nPWRCS
56
VEGA_SLEEP
H = VEGA SLEEP
L = VEGA Active
O
I/O 14: nCS1
50
LO_EN
H = RF Power ON (VCO etc.)
L = RF Power OFF
N/A
I/O 15: nCS0
48
nCS0
To make Triggered signal with R/nW
signal.
N/A
I/O Pin Assignments
Signal
Gemini Pin
GD90 Use
LT
134
This pin is used by general purpose I/O (10)
BU
120
Buzzer
6 Bit PWM
