PSB21473FV13XT Infineon Technologies, PSB21473FV13XT Datasheet - Page 35

• 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

4.2
The components realizing the terminal specific functions (Keypad Scanner, LED
Multiplex Unit and Pulse Modulation Units) run at a frequency, which is output of divider
D3. D3 can not be programmed.
The clock signal for the Terminal Specific Functions can not be disabled globally. As
described in Chapter 21.3, the different modules can be disabled separately.
4.3
For the USB Device Module the necessary clock of 48 MHz is generated using a clock
signal which is being generated from the PLL.
It’s important to note that the CPU frequency has to be greater or equal than 12
MHz to ensure a proper operation of the USB module.
The USB module clock can be disabled by setting bit USB_DIS in the CLK_CONF
register to ’1’. Before the USB interface can be used, the USB clock has to be enabled
by setting USB_DIS to ’0’ and bit UCLK of the USB Device Control Register DCR has to
be set to ’1’ (refer to Chapter 22).
A level detect mechanism enables the USB clock as soon as an appropriate level at pins
DPLS/DMNS is detected. For further information refer to the USB module description.
4.4
A bypass mechanism allows the DSP to get a clock signal with the oscillator frequency
of 15.36 MHz directly.
If the bypass is not used, the DSP runs with a PLL generated clock signal at a frequency
which can be programmed by setting bitfield DSP_DIV in register CLK_CONF according
to Table 4-1.
A change of the DSP frequency can only be performed synchronously and glitch free, if
the following steps will be applied:
• Change to the OSC as clock source ( if already running on Oscillator, it’s okay)
• 5 NOP instructions
• Change the division factor by programming CLK_CONF.DSP_DIV
• At least 50 NOP instructions recommended
• Change the clock source to PLL (if needed)
• 5 NOP instructions
Note: The NOPs are necessary to ensure to have time to change the frequency while
Data Sheet
the device is running at a much higher frequency as it will be after the change.
Terminal Specific Functions
USB
DSP
35
Clock Concept
PSB 21473
2003-03-31
INCA-D