MC68HC908GT8CFB Freescale Semiconductor, MC68HC908GT8CFB Datasheet - Page 51

• Manufacturer Part Number: MC68HC908GT8CFB
• Description: IC MCU 8K FLASH 8MHZ 44-QFP
• Manufacturer: Freescale Semiconductor
• Series: HC08r

Specifications of MC68HC908GT8CFB

• Core Processor: HC08
• Core Size: 8-Bit
• Speed: 8MHz
• Connectivity: SCI, SPI
• Peripherals: LVD, POR, PWM
• Number Of I /o: 34
• Program Memory Size: 8KB (8K x 8)
• Program Memory Type: FLASH
• Ram Size: 512 x 8
• Voltage - Supply (vcc/vdd): 2.7 V ~ 5.5 V
• Data Converters: A/D 8x8b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 44-QFP
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Eeprom Size: -

3.3.2 ADC Port I/O Pins
PTB7/AD7–PTB0/AD0 are general-purpose I/O pins that share with the ADC channels. The channel
select bits define which ADC channel/port pin will be used as the input signal. The ADC overrides the port
I/O logic by forcing that pin as input to the ADC. The remaining ADC channels/port pins are controlled by
the port I/O logic and can be used as general-purpose I/O. Writes to the port register or data direction
register (DDR) will not have any affect on the port pin that is selected by the ADC. Read of a port pin in
use by the ADC will return a logic 0.
3.3.3 Voltage Conversion
When the input voltage to the ADC equals V
input voltage equals V
straight-line linear conversion.
Freescale Semiconductor
INTERNAL DATA BUS
The ADC input voltage must always be greater than V
V
AIEN
DDA
INTERRUPT
LOGIC
MC68HC908GT16 • MC68HC908GT8 • MC68HC08GT16 Data Sheet, Rev. 5.0
. V
COCO
READ DDRBx
WRITE DDRBx
WRITE PTBx
READ PTBx
REFL
REFH
CONVERSION
,
BUS CLOCK
COMPLETE
the ADC converts it to $00. Input voltages between V
RESET
CGMXCLK
must always be greater than or equal to V
ADIV2–ADIV0
Figure 3-2. ADC Block Diagram
ADC DATA REGISTER
GENERATOR
DDRBx
REFH
PTBx
CLOCK
ADC
ADC CLOCK
NOTE
, the ADC converts the signal to $FF (full scale). If the
ADICLK
VOLTAGE IN
(V
ADC
ADIN
V
V
REFH
REFL
DISABLE
)
DISABLE
SSA
CHANNEL
REFL
SELECT
and less than
ADC CHANNEL x
.
PTBx
ADCH4–ADCH0
REFH
Functional Description
and V
REFL
are a
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