AT83C51SND1C_03 ATMEL [ATMEL Corporation], AT83C51SND1C_03 Datasheet - Page 146

• Manufacturer Part Number: AT83C51SND1C_03
• Description: Single-Chip Flash Microcontroller with MP3 Decoder and Human Interface
• Manufacturer: ATMEL [ATMEL Corporation]

Synchronous
Peripheral Interface
Figure 111. Typical Master SPI Bus Configuration
Figure 112. Typical Slave SPI Bus Configuration
146
AT8xC51SND1C
AT8xC51SND1C
MASTER
MISO
MOSI
SCK
SSn
SS1
SS0
P4.0
P4.1
P4.2
Pn.z
Pn.y
Pn.x
The AT8xC51SND1C implements a Synchronous Peripheral Interface with master and
slave modes capability.
Figure 111 shows an SPI bus configuration using the AT8xC51SND1C as master con-
nected to slave peripherals while Figure 112 shows an SPI bus configuration using the
AT8xC51SND1C as slave of an other master.
The bus is made of three wires connecting all the devices together:
•
•
•
Each slave peripheral is selected by one Slave Select pin (SS). If there is only one
slave, it may be continuously selected with SS tied to a low level. Otherwise, the
AT8xC51SND1C may select each device by software through port pins (Pn.x). Special
care should be taken not to select 2 slaves at the same time to avoid bus conflicts.
MISO
MOSI
SCK
Master Output Slave Input (MOSI): it is used to transfer data in series from the
master to a slave.
It is driven by the master.
Master Input Slave Output (MISO): it is used to transfer data in series from a slave
to the master.
It is driven by the selected slave.
Serial Clock (SCK): it is used to synchronize the data transmission both in and out
the devices through their MOSI and MISO lines. It is driven by the master for eight
clock cycles which allows to exchange one Byte on the serial lines.
SS
SS
SO
SO
DataFlash 1
Slave 1
SI
SI
SCK
SCK
SS
SS
SO
SO
DataFlash 2
Slave 2
SI
SI
SCK
SCK
MISO MOSI SCK
SS
AT8xC51SND1C
SS
SO
Slave n
Controller
SI
LCD
SCK
4109E–8051–06/03