SCI After Reset
Serial Communication Interface (SCI)
8
-5
8.3
SCI After Reset
There are several different ways to reset the SCI:
n
Hardware
RESET
signal
n
Software RESET instruction:
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 (
PC2
,
PC1
, and
PC0
all are cleared); the SCI
becomes active only when at least one of the SCI I/O signals is not programmed as
GPIO.
n
Individual reset:
During program execution, the PC2, PC1, and PC0 bits can all be cleared (that is,
individually reset), causing 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
remain unaffected so the DSP program can 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 is unknown.
n
Stop processing state reset (that is, the STOP instruction)
Executing the STOP instruction halts operation of the SCI until the DSP is
restarted, causing the SCI Status Register (SSR) to be reset. No other SCI registers
are affected by the STOP instruction.
Table 8-1 illustrates how each type of reset affects each register in the SCI.
Table 8-1. SCI Registers After Reset
Register
Bit Mnemonic
Bit Number
Reset Type
HW Reset
SW Reset
IR Reset
ST Reset
SCR
REIE
16
0
0
—
—
SCKP
15
0
0
—
—
STIR
14
0
0
—
—
TMIE
13
0
0
—
—
TIE
12
0
0
—
—
RIE
11
0
0
—
—
ILIE
10
0
0
—
—
TE
9
0
0
—
—
RE
8
0
0
—
—
WOMS
7
0
0
—
—
RWU
6
0
0
—
—
WAKE
5
0
0
—
—
SBK
4
0
0
—
—
SSFTD
3
0
0
—
—
WDS[2–0]
2–0
0
0
—
—
Summary of Contents for DSP56303
Page 1: ...DSP56303 User s Manual 24 Bit Digital Signal Processor DSP56303UM AD Revision 1 January 2001 ...
Page 52: ...JTAG OnCE Interface 2 22 DSP56303 User s Manual ...
Page 114: ...General Purpose Input Output GPIO 5 10 DSP56303 User s Manual ...
Page 212: ...GPIO Signals and Registers 8 26 DSP56303 User s Manual ...
Page 268: ...Interrupt Equates A 22 DSP56303 User s Manual ...
Page 306: ...Programming Sheets B 38 DSP56303 User s Manual ...
Page 320: ...Index 14 DSP56303 User s Manual ...