C541U_99 Datasheet, PDF (68/192 Pages) Siemens Semiconductor Group – 8-BIT CMOS MICROCONTROLLER

On-Chip Peripheral Components
C541U
6.3 SSC Interface
The C541U microcontroller provides a Synchronous Serial Channel unit, the SSC. This interface is
compatible to the popular SPI serial bus interface. It can be used for simple I/O expansion via shift
registers, for connection of a variety of peripheral components, such as A/D converters, EEPROMs
etc., or for allowing several microcontrollers to be interconnected in a master/slave structure. It
supports full-duplex or half-duplex operation and can run in a master or a slave mode.
Figure 6-14 shows the block diagram of the SSC. The central element of the SSC is an 8-bit shift
register. The input and the output of this shift register are each connected via a control logic to the
pin P1.3 / SRI (SSC Receiver In) and P1.4 / STO (SSC Transmitter Out). This shift register can be
written to (SFR STB) and can be read through the Receive Buffer Register SRB.
f _OSC
Clock Divider
...
Clock Selection
Interrupt
STB
Shift Register
SRB
Receive Buffer Register
Pin
Control
Logic
Pin P1.2 / SCLK
Pin P1.3 / SRI
Pin P1.4 / STO
Pin P1.5 / SLS
SCIEN
Int. Enable Reg.
SSCCON
Control Register
Control Logic
SCF
Status Register
Figure 6-14
SSC Block Diagram
Internal Bus
MCB03379
Semiconductor Group
6-23
1999-04-01