PSB21473FV13XT Infineon Technologies, PSB21473FV13XT Datasheet - Page 267

• Manufacturer Part Number: PSB21473FV13XT
• Manufacturer: Infineon Technologies

Specifications of PSB21473FV13XT

• Operating Supply Voltage (typ): 3.3V
• Operating Supply Voltage (min): 3.135V
• Operating Supply Voltage (max): 3.6V
• Operating Temp Range: 0C to 70C
• Operating Temperature Classification: Commercial
• Mounting: Surface Mount
• Pin Count: 144
• Lead Free Status / RoHS Status: Compliant

INCA-D
PSB 21473
The High-Speed Synchronous Serial Interfaces
Port Control
The SSCx uses three pins of Port 3 to communicate with the external world.
The 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 I/O operation, the respective port latches have to be set to '1', since 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 I/O operations via
the port latch. The direction of the port lines depends on the operating mode. The SSCx
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 tables. Using the open drain output feature helps to avoid bus contention problems
and reduces the need for hardwired hand-shaking or slave select lines. In this case it is
not always necessary to switch the direction of a port pin.
16.3
Baud Rate Generation
The serial channel SSCx has its own dedicated 16-bit baud rate generator with 16-bit
reload capability, allowing baud rate generation independent from the timers.
The baud rate generator is clocked with the CPU clock divided by 2 (f
/2). The timer
CPU
is counting downwards and can be started or stopped through the global enable bit
SSCxEN in register SSCxCON. Register SSCxBR is the dual-function Baud Rate
Generator/Reload register. Reading SSCxBR, while the SSCx is enabled, returns the
content of the timer. Reading SSCxBR, while the SSCx is disabled, returns the
programmed reload value. In this mode the desired reload value can be written to
SSCxBR.
Note: Never write to SSCxBR, while the SSCx is enabled.
The formulas below calculate either the resulting baud rate for a given reload value, or
the required reload value for a given baudrate:
f
f
CPU
CPU
B
=
SSCBR = (
) - 1
SSC
2 * (<SSCBR> + 1)
2 * Baudrate
SSC
<SSCxBR> represents the content of the reload register, taken as unsigned 16-bit
integer.
The maximum baud rate that can be achieved when using a CPU clock of 36 MHz is 18
MBaud in SSCx Master Mode (<SSCxBR>= ’0
’), while in SSCx Slave Mode the
d
maximum baud rate is 9 MBaud (<SSCxBR>= ’1
’; - <SSCxBR>=’0
’ is not allowed in
d
d
Data Sheet
267
2003-03-31