收藏本站
101
AT89C51ID2
4289C–8051–11/05
Figure 38. Full-Duplex Master-Slave Interconnection
Master Mode
The SPI operates in Master mode when the Master bit, MSTR
(1), in the SPCON register
is set. Only one Master SPI device can initiate transmissions. Software begins the trans-
mission from a Master SPI Module by writing to the Serial Peripheral Data Register
(SPDAT). If the shift register is empty, the Byte is immediately transferred to the shift
register. The Byte begins shifting out on MOSI pin under the control of the serial clock,
SCK. Simultaneously, another Byte shifts in from the Slave on the Master’s MISO pin.
The transmission ends when the Serial Peripheral transfer data flag, SPIF, in SPSTA
becomes set. At the same time that SPIF becomes set, the received Byte from the Slave
is transferred to the receive data register in SPDAT. Software clears SPIF by reading
the Serial Peripheral Status register (SPSTA) with the SPIF bit set, and then reading the
SPDAT.
Slave Mode
The SPI operates in Slave mode when the Master bit, MSTR
(2), in the SPCON register is
cleared. Before a data transmission occurs, the Slave Select pin, SS, of the Slave
device must be set to ’0’. SS must remain low until the transmission is complete.
In a Slave SPI Module, data enters the shift register under the control of the SCK from
the Master SPI Module. After a Byte enters the shift register, it is immediately trans-
ferred to the receive data register in SPDAT, and the SPIF bit is set. To prevent an
overflow condition, Slave software must then read the SPDAT before another Byte
enters the shift register
(3). A Slave SPI must complete the write to the SPDAT (shift reg-
ister) at least one bus cycle before the Master SPI starts a transmission. If the write to
the data register is late, the SPI transmits the data already in the shift register from the
previous transmission. The maximum SCK frequency allowed in slave mode is F
CLK PERIPH
/4.
Transmission Formats
Software can select any of four combinations of serial clock (SCK) phase and polarity
using two bits in the SPCON: the Clock Polarity (CPOL
(4)) and the Clock Phase
(CPHA
4). CPOL defines the default SCK line level in idle state. It has no significant
effect on the transmission format. CPHA defines the edges on which the input data are
sampled and the edges on which the output data are shifted (Figure 39 and Figure 40).
The clock phase and polarity should be identical for the Master SPI device and the com-
municating Slave device.
8-bit Shift register
SPI
Clock Generator
Master MCU
8-bit Shift register
MISO
MOSI
SCK
VSS
VDD
SS
Slave MCU
1.
The SPI Module should be configured as a Master before it is enabled (SPEN set). Also,
the Master SPI should be configured before the Slave SPI.
2.
The SPI Module should be configured as a Slave before it is enabled (SPEN set).
3.
The maximum frequency of the SCK for an SPI configured as a Slave is the bus clock
speed.
4.
Before writing to the CPOL and CPHA bits, the SPI should be disabled (SPEN = ’0’).
发布紧急采购，3分钟左右您将得到回复。

采购需求

(若只采购一条型号，填写一行即可)

发布成功！您可以继续发布采购。也可以进入我的后台，查看报价

发布成功！您可以继续发布采购。也可以进入我的后台，查看报价

*型号 *数量 厂商 批号 封装
添加更多采购

我的联系方式

*
*
*
相关PDF资料
AT89C51IC2-SLSIL IC 8051 MCU FLASH 32K 44PLCC
AT89C51CC03U-RLTIM IC 8051 MCU FLASH 64K 44VQFP
PIC24EP64MC204-I/PT MCU 16BIT 64KB FLASH 44TQFP
AT89C51CC03U-RDTIM IC 8051 MCU FLASH 64K 64VQFP
AT89C51CC03U-7CTIM IC 8051 MCU FLASH 64K 64BGA
AT89C51CC03C-S3SIM IC 8051 MCU FLASH 64K 52PLCC
AT89C51CC03C-RLTIM IC 8051 MCU FLASH 64K 44VQFP
AT89C51CC03C-7CTIM IC 8051 MCU FLASH 64K 64BGA
相关代理商/技术参数
AT89C51ID2-RLTUM 功能描述:8位微控制器 -MCU C51ID2 64K FLASH 32KHz 3-5.5V RoHS:否 制造商:Silicon Labs 核心:8051 处理器系列:C8051F39x 数据总线宽度:8 bit 最大时钟频率:50 MHz 程序存储器大小:16 KB 数据 RAM 大小:1 KB 片上 ADC:Yes 工作电源电压:1.8 V to 3.6 V 工作温度范围:- 40 C to + 105 C 封装 / 箱体:QFN-20 安装风格:SMD/SMT
AT89C51ID2-SLRIM 功能描述:IC MCU FLASH 8051 64K 5V 44-PLCC RoHS:否 类别:集成电路 (IC) >> 嵌入式 - 微控制器， 系列:89C 标准包装:1,500 系列:AVR® ATtiny 核心处理器:AVR 芯体尺寸:8-位 速度:16MHz 连通性:I²C，LIN，SPI，UART/USART，USI 外围设备:欠压检测/复位，POR，PWM，温度传感器，WDT 输入/输出数:16 程序存储器容量:8KB（4K x 16） 程序存储器类型:闪存 EEPROM 大小:512 x 8 RAM 容量:512 x 8 电压 - 电源 (Vcc/Vdd):2.7 V ~ 5.5 V 数据转换器:A/D 11x10b 振荡器型:内部 工作温度:-40°C ~ 125°C 封装/外壳:20-SOIC（0.295"，7.50mm 宽） 包装:带卷 (TR)
AT89C51ID2-SLRUM 功能描述:8位微控制器 -MCU C51ID2 64K FLASH TWI 32KHz 5V RoHS:否 制造商:Silicon Labs 核心:8051 处理器系列:C8051F39x 数据总线宽度:8 bit 最大时钟频率:50 MHz 程序存储器大小:16 KB 数据 RAM 大小:1 KB 片上 ADC:Yes 工作电源电压:1.8 V to 3.6 V 工作温度范围:- 40 C to + 105 C 封装 / 箱体:QFN-20 安装风格:SMD/SMT
AT89C51ID2-SLSIM 制造商:ATMEL 制造商全称:ATMEL Corporation 功能描述:8-bit Flash Microcontroller
AT89C51ID2-SLSUM 功能描述:8位微控制器 -MCU 64K FLASH 32KHz 3.5-5V Ind. RoHS:否 制造商:Silicon Labs 核心:8051 处理器系列:C8051F39x 数据总线宽度:8 bit 最大时钟频率:50 MHz 程序存储器大小:16 KB 数据 RAM 大小:1 KB 片上 ADC:Yes 工作电源电压:1.8 V to 3.6 V 工作温度范围:- 40 C to + 105 C 封装 / 箱体:QFN-20 安装风格:SMD/SMT
AT89C51ID2-SMSIM 制造商:ATMEL 制造商全称:ATMEL Corporation 功能描述:8-bit Flash Microcontroller
AT89C51ID2-UM 制造商:ATMEL 制造商全称:ATMEL Corporation 功能描述:8-bit Flash Microcontroller
AT89C51RB2 制造商:ATMEL 制造商全称:ATMEL Corporation 功能描述:8-bit Microcontroller with 16K/ 32K Bytes Flash