PMMA7450LR2 Freescale Semiconductor, Inc, PMMA7450LR2 Datasheet - Page 10

• Manufacturer Part Number: PMMA7450LR2
• Description: ?2g/?4g/?8g Three Axis Low-g Digital Output Accelerometer
• Manufacturer: Freescale Semiconductor, Inc

MULTIPLE BYTES WRITE
register address commands after a write command is
received. Therefore, after following the steps of a single byte
communication as a digital communication. The SPI
communication is primarily used for synchronous serial
communication between a master device and one or more
slave devices. See
configure one master with two MMA7450L devices. The
MMA7450L is always operated as a slave device. Typically,
the master device would be a microcontroller which would
drive the clock (SPC) and chip select (CS) signals.
lines: CS, SPC, SDI, and SDO. The CS, also known as Chip
Select, is the slave device enable which is controlled by the
SPI master. CS is driven low at the start of a transmission. CS
is then driven high at the end of a transmission. SPC is the
Serial Port Clock which is also controlled by the SPI master.
SDI and SDO are the Serial Port Data Input and the Serial
Port Data Output. The SDI and SDO data lines are driven at
the falling edge of the SPC and should be captured at the
rising edge of the SPC.
10
MMA7450L
The MMA7450L automatically increments the received
The MMA7450L also uses serial peripheral interface
The SPI interface consists of two control lines and two data
Figure 10. Multiple Byte Writes - The Master (MCU) is writing to multiple sequential registers of the MMA7450L
SPI SLAVE INTERFACE
Figure 16
Figure 13. SPI Timing Diagram for 8-Bit Register Write (3 Wire Mode)
Figure 11. SPI Timing Diagram for 8-Bit Register Read (4 Wire Mode)
Figure 12. SPI Timing Diagram for 8-Bit Register Read (3 Wire Mode)
for an example of how to
write, multiple bytes of data can be written to sequential
registers after each MMA7450L acknowledgment (ACK) is
received. See
clock pulses or in multiples of 8, in the case of a multiple byte
read/write.
6-bit address, and 1-bit don’t care bit. (1-bit R/W=0 + 6-bits
address + 1-bit don’t care). The data to read is sent by the
SPI interface during the next transfer. See
Figure 12
3 wire modes, respectively.
command must be sent to the MMA7450L. The write
command consists of an MSB (0=read, 1=write) to indicate
writing to the MMA7450L register, followed by a 6-bit address
and 1 don’t care bit.
transfer. See
data write.
Read and write register commands are completed in 16
A SPI read transfer consists of a 1-bit Read/Write signal, a
In order to write to one of the 8-bit registers, an 8-bit write
The command should then be followed the 8-bit data
for the timing diagram for an 8-bit read in 4 wire and
Figure 13
Figure
SPI WRITE OPERATION
SPI READ OPERATION
10.
for the timing diagram for an 8-bit
Freescale Semiconductor
Figure 11
Sensors
and