參數(shù)資料
型號: MC68HC11A1CFN2
廠商: MOTOROLA INC
元件分類: 微控制器/微處理器
英文描述: HCMOS Single-Chip Microcontroller
中文描述: 8-BIT, 2 MHz, MICROCONTROLLER, PQCC52
封裝: PLASTIC, LCC-52
文件頁數(shù): 60/158頁
文件大?。?/td> 776K
代理商: MC68HC11A1CFN2
MOTOROLA
6-2
SERIAL PERIPHERAL INTERFACE
MC68HC11A8
TECHNICAL DATA
6
6.2.3 Serial Clock (SCK)
The serial clock is used to synchronize data movement both in and out of the device
through its MOSI and MISO lines. The master and slave devices are capable of ex-
changing a byte of information during a sequence of eight clock cycles. Since SCK is
generated by the master device, this line becomes an input on a slave device.
As shown in
Figure 6-1
, four possible timing relationships may be chosen by using
control bits CPOL and CPHA in the serial peripheral control register (SPCR). Both
master and slave devices must operate with the same timing. The master device al-
ways places data on the MOSI line a half-cycle before the clock edge (SCK), in order
for the slave device to latch the data.
Two bits (SPR0 and SPR1) in the SPCR of the master device select the clock rate. In
a slave device, SPR0 and SPR1 have no effect on the operation of the SPI.
6.2.4 Slave Select (SS)
The slave select (SS) input line is used to select a slave device. It has to be low prior
to data transactions and must stay low for the duration of the transaction.
The SS line on the master must be tied high. If it goes low, a mode fault error flag
(MODF) is set in the serial peripheral status register (SPSR). The SS pin can be se-
lected to be a general-purpose output by writing a one in bit 5 of the port D data direc-
tion register, thus disabling the mode fault circuit. The other three SPI lines are
dedicated to the SPI whenever the SPI is on.
Figure 6-1 Data Clock Timing Diagram
When CPHA = 0, the shift clock is the OR of SS with SCK. In this clock phase mode,
SS must go high between successive characters in an SPI message. When CPHA =
1, SS may be left low for several SPI characters. In cases where there is only one SPI
slave MCU, its SS line could be tied to V
SS
as long as CPHA = 1 clock modes are used.
SCK CYCLE #
(FOR REFERENCE)
1
2
3
4
5
6
7
8
SCK (CPOL = 0)
SCK (CPOL = 1)
(CPHA = 0) DATA OUT
(CPHA = 1) DATA OUT
SS (TO SLAVE)
SAMPLE INPUT
SAMPLE INPUT
MSB
6
5
4
3
2
1
LSB
MSB
6
5
4
3
2
1
LSB
SPI TRANSFER FORMAT
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相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
MC68HC11A1CFN3 制造商:Rochester Electronics LLC 功能描述:
MC68HC11A1CFNE3 功能描述:8位微控制器 -MCU 8B MCU 256RAM A/D EE 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(fēng)格:SMD/SMT
MC68HC11A1CFNE3 制造商:Freescale Semiconductor 功能描述:8-BIT MICROCONTROLLER IC
MC68HC11A1CFNE3R 功能描述:8位微控制器 -MCU 8B MCU 256RAM A/D EE 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(fēng)格:SMD/SMT
MC68HC11A1CFU2 制造商:MOTOROLA 制造商全稱:Motorola, Inc 功能描述:HCMOS Single-Chip Microcontroller