ST92150JDV1QAuto STMicroelectronics, ST92150JDV1QAuto Datasheet - Page 258

• Manufacturer Part Number: ST92150JDV1QAuto
• Description: 8/16-bit single voltage Flash MCU family with RAM, E3 TM(emulated EEPROM), CAN 2.0B and J1850 BLPD
• Manufacturer: STMicroelectronics

Specifications of ST92150JDV1QAuto

• Internal Memory: Single Voltage FLASH up to 256 Kbytes, RAM up to 8Kbytes, 1K byte E3 TM (Emulated EEPROM)
• Minimum Instruction Time: 83 ns (24 MHz int. clock)

ST92124xxx-Auto/150xxxxx-Auto/250xxxx-Auto
SERIAL PERIPHERAL INTERFACE (Cont’d)
10.7.4.7 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
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 slave device during a
transmission.
Figure 125. Single Master Configuration
258/430
9
5V
Figure
MOSI
SS
SCK
SCK
MOSI
MCU
Master
Slave
MCU
125).
MISO
MISO
SS
MOSI
SCK
Slave
MCU
MISO
SS
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 SPDR reg-
ister.
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 SPCR register and the MODF
bit in the SPSR register.
MOSI
SCK
MCU
Slave
MISO
SS
MOSI
SCK
Slave
MCU
MISO
SS