TMS320F28335, TMS320F28334, TMS320F28332
TMS320F28235, TMS320F28234, TMS320F28232
Digital Signal Controllers (DSCs)
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SPRS439C–JUNE 2007–REVISED FEBRUARY 2008
Time between samples
GPyCTRL Reg
Input Signal
Qualification
GPIOx
SYNC
Qualified By 3
or 6 Samples
GPxQSEL
SYSCLKOUT
Number of Samples
Figure 4-19. Qualification Using Sampling Window
The sampling period is specified by the QUALPRD bits in the GPxCTRL register and is configurable in
groups of 8 signals. It specifies a multiple of SYSCLKOUT cycles for sampling the input signal. The
sampling window is either 3-samples or 6-samples wide and the output is only changed when ALL
samples are the same (all 0s or all 1s) as shown in Figure 4-18 (for 6 sample mode).
•
•
No Synchronization (GPxQSEL1/2=1,1): This mode is used for peripherals where synchronization is
not required (synchronization is performed within the peripheral).
Due to the multi-level multiplexing that is required on the device, there may be cases where a peripheral
input signal can be mapped to more then one GPIO pin. Also, when an input signal is not selected, the
input signal will default to either a 0 or 1 state, depending on the peripheral.
4.14 External Interface (XINTF)
This section gives a top-level view of the external interface (XINTF) that is implemented on the
F2833x/F2823x devices.
The XINTF is a non-multiplexed asynchronous bus, similar to the 2812 XINTF. The XINTF is mapped into
three fixed zones shown in Figure 4-20.
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Peripherals
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