SAF-C164SM Infineon Technologies, SAF-C164SM Datasheet - Page 243

• Manufacturer Part Number: SAF-C164SM
• Description: 16-Bit CMOS Microcontroller
• Manufacturer: Infineon Technologies

12.4
The SSC uses three pins of PORT0 to communicate with the external world. Pin P0H.7/
SCLK serves as the clock line, while pins P0H.5/MRST (Master Receive/Slave Transmit)
and P0H.6/MTSR (Master Transmit/Slave Receive) serve as the serial data input/output
lines. Operation of these pins depends on the selected operating mode (master or
slave). In order to enable the alternate output functions of these pins instead of the
general purpose IO operation, the respective port latches must be set to ‘1’, because the
port latch outputs and the alternate output lines are ANDed. When an alternate data
output line is not used (function disabled), it is held at a high level, allowing IO operations
via the port latch. The direction of the port lines depends on the operating mode. The
SSC will automatically use the correct alternate input or output line of the ports when
switching modes. The direction of the pins, however, must be programmed by the user,
as shown in the following tables.
various modes and pins.
Table 12-1
Pin
SCLK
MTSR
MRST
Note: In
User’s Manual
mode, however, it is recommended to set these bits to ‘1’, so they are already in
the correct state when switching between master and slave modes.
Table
Function Port Latch
Serial
Clock
Output
Serial
Data
Output
Serial
Data
Input
Port Control
SSC Port Control
12-1, an ‘x’ means that the actual value is irrelevant in the respective
P0H.7 = ‘1’
P0H.6 = ‘1’
P0H.5 = ‘x’
Master Mode
Direction
DP0H.7 = ‘1’ Serial
DP0H.6 = ‘1’ Serial
DP0H.5 = ‘0’ Serial
Table 12-1
12-12
High-Speed Synchronous Serial Interface
summarizes the required values for the
Function Port Latch
Clock
Input
Data
Input
Data
Output
P0H.7 = ‘x’
P0H.6 = ‘x’
P0H.5 = ‘1’
Slave Mode
C164CM/C164SM
Derivatives
Direction
DP0H.7 = ‘0’
DP0H.6 = ‘0’
DP0H.5 = ‘1’
V1.0, 2002-02