參數(shù)資料
型號: ST72254G1B5
英文描述: 8-BIT MCU WITH SINGLE VOLTAGE FLASH MEMORY. ADC. 16-BIT TIMERS. SPI.
中文描述: 8位單電壓閃存微控制器。 ADC的。 16位定時器。的SPI。
文件頁數(shù): 106/140頁
文件大?。?/td> 1349K
代理商: ST72254G1B5
ST72104G, ST72215G, ST72216G, ST72254G
68/140
SERIAL PERIPHERAL INTERFACE (Cont’d)
12.3.4.7 Single Master and Multimaster Configurations
There are two types of SPI systems:
– Single Master System
– Multimaster System
Single Master System
A typical single master system may be configured,
using an MCU as the master and four MCUs as
slaves (see Figure 42).
The master device selects the individual slave de-
vices by using four pins of a parallel port to control
the four SS pins of the slave devices.
The SS pins are pulled high during reset since the
master device ports will be forced to be inputs at
that time, thus disabling the slave devices.
Note: To prevent a bus conflict on the MISO line
the master allows only one active slave device
during a transmission.
For more security, the slave device may respond
to the master with the received data byte. Then the
master will receive the previous byte back from the
slave device if all MISO and MOSI pins are con-
nected and the slave has not written its DR regis-
ter.
Other transmission security methods can use
ports for handshake lines or data bytes with com-
mand fields.
Multi-master System
A multi-master system may also be configured by
the user. Transfer of master control could be im-
plemented using a handshake method through the
I/O ports or by an exchange of code messages
through the serial peripheral interface system.
The multi-master system is principally handled by
the MSTR bit in the CR register and the MODF bit
in the SR register.
Figure 42. Single Master Configuration
MISO
MOSI
MISO
SS
SCK
5V
Po
rt
s
Slave
MCU
Slave
MCU
Slave
MCU
Slave
MCU
Master
MCU
相關(guān)PDF資料
PDF描述
ST72254G1B3 8-BIT MCU WITH SINGLE VOLTAGE FLASH MEMORY. ADC. 16-BIT TIMERS. SPI.
ST72254G1B1 8-BIT MCU WITH SINGLE VOLTAGE FLASH MEMORY. ADC. 16-BIT TIMERS. SPI.
ST72312N5B6 8-BIT MICROCONTROLLER
ST72312N6B6 8-BIT MICROCONTROLLER
ST72312R4Q6 8-BIT MICROCONTROLLER
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
ST72254G1B5/XXX 制造商:STMICROELECTRONICS 制造商全稱:STMicroelectronics 功能描述:8-BIT MCU WITH SINGLE VOLTAGE FLASH MEMORY, ADC, 16-BIT TIMERS, SPI, IC INTERFACES
ST72254G1B6 制造商:未知廠家 制造商全稱:未知廠家 功能描述:8-BIT MCU WITH SINGLE VOLTAGE FLASH MEMORY. ADC. 16-BIT TIMERS. SPI.
ST72254G1B6/XXX 制造商:STMICROELECTRONICS 制造商全稱:STMicroelectronics 功能描述:8-BIT MCU WITH SINGLE VOLTAGE FLASH MEMORY, ADC, 16-BIT TIMERS, SPI, IC INTERFACES
ST72254G1B7 制造商:未知廠家 制造商全稱:未知廠家 功能描述:8-BIT MCU WITH SINGLE VOLTAGE FLASH MEMORY. ADC. 16-BIT TIMERS. SPI.
ST72254G1B7/XXX 制造商:STMICROELECTRONICS 制造商全稱:STMicroelectronics 功能描述:8-BIT MCU WITH SINGLE VOLTAGE FLASH MEMORY, ADC, 16-BIT TIMERS, SPI, IC INTERFACES