
167/199
ST90158 - MULTIPROTOCOL SERIAL COMMUNICATIONS INTERFACE (SCI-M)
MULTIPROTOCOL SERIAL COMMUNICATIONS INTERFACE
(Cont’d)
BAUD RATE GENERATOR HIGH REGISTER
(BRGHR)
R252 - Read/Write
Reset value: undefined
BAUD RATE GENERATOR LOW REGISTER
(BRGLR)
R253
-
Read/Write
Reset value: undefined
Bit 15:0 =
Baud Rate Generator MSB and LSB.
The Baud Rate generator is a programmable di-
vide by “N” counter which can be used to generate
the clocks for the transmitter and/or receiver. This
counter divides the clock input by the value in the
Baud Rate Generator Register. The minimum
baud rate divisor is 2 and the maximum divisor is
2
16
-1. After initialization of the baud rate genera-
tor, the divisor value is immediately loaded into the
counter. This prevents potentially long random
counts on the initial load. If set to 0 or 1, the Baud
Rate Generator is stopped.
SYNCHRONOUS INPUT CONTROL (SICR)
R254
- Read/Write
Reset value: 0000 0011 (03h)
Bit 7 =
SMEN
:
Synchronous Mode Enable
.
0: Disable all features relating to Synchronous
mode (the contents of SICR and SOCR are ig-
nored).
1: Select Synchronous mode with its programmed
I/O configuration.
Bit 6 =
INPL
:
SIN Input Polarity
.
0: Polarity not inverted.
1: Polarity inverted.
Note:
INPL only affects received data. In Auto-
Echo mode SOUT = SIN even if INPL is set. In
Loop-Back mode the state of the INPL bit is irrele-
vant.
Bit 5 =
XCKPL
:
Receiver Clock Polarity
.
0: RXCLK is active on the rising edge.
1: RXCLK is active on the falling edge.
Note:
XCKPL only affects the receiver clock. In
Auto-Echo mode CLKOUT = RXCLK independ-
ently of the XCKPL status. In Loop-Back the state
of the XCKPL bit is irrelevant.
Bit 4 =
DCDEN
:
DCD Input Enable
.
0: Disable hardware synchronization.
1: Enable hardware synchronization.
Note:
When DCDEN is set, RXCLK drives the re-
ceiver section only during the active level of the
DCD input (DCD works as a gate on RXCLK, in-
forming the MCU that a transmitting device is
sending a synchronous frame to it).
Bit 3 =
DCDPL
:
DCD Input Polarity
.
0: The DCD input is active when LOW.
1: The DCD input is active when HIGH.
Note:
DCDPL only affects the gating activity of the
receiver clock. In Auto-Echo mode RTS = DCD in-
dependently of DCDPL. In Loop-Back mode, the
state of DCDPL is irrelevant.
Bit 2 =
:
All Input Disable
.
0: Enable SIN/RXCLK/DCD inputs.
1: Disable SIN/RXCLK/DCD inputs.
Bit 1:0 = “Don't Care”
15
8
BG15
BG14
BG13
BG12
BG11
BG10
BG9
BG8
7
0
BG7
BG6
BG5
BG4
BG3
BG2
BG1
BG0
7
0
SMEN
INPL
XCKPL
DCDE
N
DCDP
L
INPEN
X
X
9