參數(shù)資料
型號： MC705JP7CPE
廠商： Freescale Semiconductor
文件頁數(shù)： 155/164頁
文件大小： 0K
描述： IC MCU 8BIT 224 BYTES RAM 28PDIP
標準包裝： 13
系列： HC05
核心處理器： HC05
芯體尺寸： 8-位
速度： 2.1MHz
連通性： SIO
外圍設備： POR，溫度傳感器，WDT
輸入/輸出數(shù)： 22
程序存儲器容量： 6KB（6K x 8）
程序存儲器類型： OTP
RAM 容量： 224 x 8
電壓 - 電源 (Vcc/Vdd)： 2.7 V ~ 5.5 V
數(shù)據(jù)轉(zhuǎn)換器： A/D 4x12b
振蕩器型： 內(nèi)部
工作溫度： -40°C ~ 85°C
封裝/外殼： 28-DIP（0.600"，15.24mm）
包裝： 管件
Analog Subsystem
MC68HC705JJ7 MC68HC705JP7 Advance Information Data Sheet, Rev. 4.1
90
Freescale Semiconductor
8.6.1 Absolute Voltage Readings
The absolute value of a voltage measurement can be calculated in software by first taking a reference
reading from a fixed source and then comparing subsequent unknown voltages to that reading as a
percentage of the reference voltage multiplied times the known reference value.
The accuracy of absolute readings will depend on the error sources taken into account using the features
of the analog subsystem and appropriate software as described in Table 8-6. As can be seen from this
table, most of the errors can be reduced by frequent comparisons to a known voltage, use of the inverted
comparator inputs, and averaging of multiple samples.
8.6.1.1 Internal Absolute Reference
If a stable source of VDD is provided, the reference measurement point can be internally selected. In this
case, the reference reading can be taken by setting the VREF bit and clearing the MUX1:4 bits in the
AMUX register. This connects the channel selection bus to the VDD pin. To stay within the VMAX range,
the DHOLD bit should be used to select the 1/2 divided input.
8.6.1.2 External Absolute Reference
If a stable external source is provided, the reference measurement point can be any one of the channel
selected pins from PB1–PB4. In this case the reference reading can be taken by setting the MUX bit in
the AMUX which connects channel selection bus to the pin connected to the external reference source.
If the external reference is greater than VDD –1.5 volts, then the DHOLD bit should be used to select the
1/2 divided input.
Table 8-6. Absolute Voltage Reading Errors
Error Source
Accuracy Improvements Possible
In Hardware
In Software
Change in reference voltage Provide closer tolerance reference
Calibration and storage of reference source over
temperature and supply voltage
Change in magnitude of
ramp current source
Not adjustable
Compare unknown with recent measurement
from reference
Non-linearity of ramp
current source vs. voltage
Not adjustable
Calibration and storage of voltages at 1/4, 1/2,
3/4, and FS
Frequency shift in internal
low-power oscillator
Use external oscillator with crystal
Compare unknown with recent measurement
from reference
Sampling capacitor leakage
Use faster conversion times
Compare unknown with recent measurement
from reference
Internal voltage divider ratio
Not adjustable
Compare unknown with recent measurement
from reference OR avoid use of divided input
Input offset voltage of
comparator 2
Not adjustable
Sum two readings on reference or unknown
using INV and INV control bit and divide by 2
(average of both)
Noise internal to MCU
Close decoupling at VDD and VSS pins and
reduce supply source impedance
Average multiple readings on both the reference
and the unknown voltage
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相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
MC705JP7CPE 制造商:Freescale Semiconductor 功能描述:IC 8BIT MCU 68HC05 2.1MHZ DIP-28
MC705K1CP 制造商:Motorola Inc 功能描述:16 PIN DIP INTEGRATED CIRCUIT
MC705L16CFUE 功能描述:8位微控制器 -MCU 8B MCU W/ EPROM RoHS:否 制造商:Silicon Labs 核心:8051 處理器系列:C8051F39x 數(shù)據(jù)總線寬度:8 bit 最大時鐘頻率:50 MHz 程序存儲器大小:16 KB 數(shù)據(jù) RAM 大小:1 KB 片上 ADC:Yes 工作電源電壓:1.8 V to 3.6 V 工作溫度范圍:- 40 C to + 105 C 封裝 / 箱體:QFN-20 安裝風格:SMD/SMT
MC705P6ACDWE 功能描述:8位微控制器 -MCU MCU 176 BYTES RAM A/D RoHS:否 制造商:Silicon Labs 核心:8051 處理器系列:C8051F39x 數(shù)據(jù)總線寬度:8 bit 最大時鐘頻率:50 MHz 程序存儲器大小:16 KB 數(shù)據(jù) RAM 大小:1 KB 片上 ADC:Yes 工作電源電壓:1.8 V to 3.6 V 工作溫度范圍:- 40 C to + 105 C 封裝 / 箱體:QFN-20 安裝風格:SMD/SMT
MC705P6ACDWE 制造商:Freescale Semiconductor 功能描述:8-Bit Microcontroller IC
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