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TMS320F28069, TMS320F28068, TMS320F28067, TMS320F28066
TMS320F28065, TMS320F28064, TMS320F28063, TMS320F28062
SPRS698F – NOVEMBER 2010 – REVISED MARCH 2016
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TMS320F28069 TMS320F28068 TMS320F28067 TMS320F28066 TMS320F28065
TMS320F28064 TMS320F28063 TMS320F28062
Detailed Description
Copyright © 2010–2016, Texas Instruments Incorporated
The user can select the type of input qualification for each GPIO pin through the GPxQSEL1/2 registers
from four choices:
•
Synchronization To SYSCLKOUT Only (GPxQSEL1/2 = 0, 0): This is the default mode of all GPIO pins
at reset and it simply synchronizes the input signal to the system clock (SYSCLKOUT).
•
Qualification Using Sampling Window (GPxQSEL1/2 = 0, 1 and 1, 0): In this mode the input signal,
after synchronization to the system clock (SYSCLKOUT), is qualified by a specified number of cycles
before the input is allowed to change.
•
The sampling period is specified by the QUALPRD bits in the GPxCTRL register and is configurable in
groups of 8 signals. The sampling period 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 multilevel 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.