Sci After Reset - Motorola DSP56305 User Manual

Serial Communication Interface (SCI)
Operating Modes
8.4.1

SCI After Reset

There are four different methods of resetting the SCI.
1. Hardware reset
2. Software reset
Both hardware and software resets clear the Port Control Register bits, which
configure all I/O as GPIO input. The SCI remains in the Reset state as long as all
SCI signals are programmed as GPIO (CC2, CC1, and CC0 all are cleared); the SCI
becomes active only when at least one of the SCI I/O signals is not programmed
as GPIO.
3. Individual reset
During program execution, the CC2, CC1, and CC0 bits can be cleared (individual
reset), which causes the SCI to stop serial activity and enter the Reset state. All
SCI status bits are set to their Reset state. However, the contents of the SCR are
not affected, allowing the DSP program to reset the SCI separately from the other
internal peripherals. During individual reset, internal DMA accesses to the data
registers of the SCI are not valid and the data read will be unknown.
4. Stop processing state reset
Executing the STOP instruction halts operation of the SCI until the DSP is
restarted, causing the SSR to be reset. No other SCI registers are affected by the
STOP instruction. Table 8-3 illustrates how each type of reset affects each register
in the SCI.
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