MC9S08GT8ACFBE Freescale Semiconductor, MC9S08GT8ACFBE Datasheet - Page 231

• Manufacturer Part Number: MC9S08GT8ACFBE
• Description: IC MCU 8K FLASH 1K RAM 44-QFP
• Manufacturer: Freescale Semiconductor
• Series: HCS08r

Specifications of MC9S08GT8ACFBE

• Core Processor: HCS08
• Core Size: 8-Bit
• Speed: 40MHz
• Connectivity: I²C, SCI, SPI
• Peripherals: LVD, POR, PWM, WDT
• Number Of I /o: 36
• Program Memory Size: 8KB (8K x 8)
• Program Memory Type: FLASH
• Ram Size: 1K x 8
• Voltage - Supply (vcc/vdd): 1.8 V ~ 3.6 V
• Data Converters: A/D 8x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 44-QFP
• Processor Series: S08GT
• Core: HCS08
• Data Bus Width: 8 bit
• Data Ram Size: 1 KB
• Interface Type: I2C/SCI/SPI
• Maximum Clock Frequency: 40 MHz
• Number Of Programmable I/os: 36
• Operating Supply Voltage: 3.6 V
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• 3rd Party Development Tools: EWS08
• Development Tools By Supplier: M68EVB908GB60E, M68DEMO908GB60E
• Minimum Operating Temperature: - 40 C
• On-chip Adc: 8-ch x 10-bit
• For Use With: M68DEMO908GB60E - BOARD DEMO MC9S08GB60M68EVB908GB60E - BOARD EVAL FOR MC9S08GB60
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

When the S/H machine is not sampling, it disables its own internal clocks.The input analog signals are
unipolar. The signals must fall within the potential range of V
required to perform special conversions (i.e., convert V
Proper sampling is dependent on the following factors:
In cases where there is no external filtering capacitance, the sampling error is determined by the number
of time constants of charging and the change in input voltage relative to the resolution of the ATD:
The maximum sampling error (assuming maximum change on the input voltage) will be:
In the case where an external filtering capacitance is applied, the sampling error can be reduced based on
the size of the source capacitor (C
source impedance (R
Freescale Semiconductor
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Analog source impedance (the real portion, R
this data sheet) — This is the resistive (or real, in the case of high frequencies) portion of the
network driving the analog input voltage V
Analog source capacitance (C
large enough) may help the analog source network charge the ATD input in the case of high R
ATD input resistance (R
circuit in the path between the external ATD input and the ATD sample and hold circuit. This
resistance varies with temperature, voltage, and process variation but a worst case number is
necessary to compute worst case sample error.
ATD input capacitance (C
ATD sample and hold circuit. This capacitance varies with temperature, voltage, and process
variation but a worst case number is necessary to compute worst case sample error.
ATD conversion clock frequency (f
the clock input to the ATD and is dependent on the bus clock frequency and the ATD prescaler.
This frequency determines the width of the sample window, which is 14 ATDCLK cycles.
Input sample frequency (f
This is the frequency that a given input is sampled.
Delta-input sample voltage (∆V
(intended for conversion) and the previously sampled voltage (which may be from a different
channel). In non-continuous convert mode, this is assumed to be the greater of (V
(V
account for leakage and other losses.
Delta-analog input voltage (∆V
the input voltage during the last conversion on a given channel. This is based on the slew rate of
the input.
AIN
– V
sampling error in LSB (E
REFL
# of time constants (τ) = (14 / f
E
S
AS
= (3.6/3.6) * e
). In continuous convert mode, 5 LSB should be added to the known difference to
), C
AS
will charge C
AIN
SAMP
AIN
AS
MC9S08GT16A/GT8A Data Sheet, Rev. 1
–(14/((7 k + 10 k) * 50 p * 2 M))
– maximum value 7 kΩ) — This is the internal resistance of the ATD
) relative to the analog input capacitance (C
AS
– maximum value 25 pF) — This is the internal capacitance of the
AIN
SAMP
– see the electrical characteristics at the end of this data sheet) —
) — This is the filtering capacitance on the analog input, which (if
) — This is the difference between the current input voltage and
ATDCLK
S
) = 2
AIN
) — This is the difference between the current input voltage
to a value of:
ATDCLK
N
AIN
* (∆V
– maximum value 2 MHz) — This is the frequency of
AS
.
) / ((R
REFL
– see the electricals characteristics at the end of
SAMP
* 1024 = 0.271 LSB
AS
and V
SSAD
/ (V
+ R
AIN
REFH
REFH
to V
) * C
).
DDAD
- V
Analog-to-Digital Converter (S08ATDV3)
AIN
REFL
)
. The S/H machine is not
AIN
)) * e
). Ignoring the analog
−τ
REFH
– V
Eqn. 14-1
Eqn. 14-2
AIN
) and
AS
231
.