A N 9 3
20
Rev. 1.4
The UART interface synchronizes on the start bits of incoming characters and samples the data bit field and stop
bits. The interface is designed to accommodate character lengths of 8, 9, 10, and 11 bits giving data fields of 6, 7,
8, or 9 bits. Data width can be set to 6, 7, or 8 bits with the AT\Bn command. Parity can be set to odd, even, mark,
or space by the AT\Pn command in conjunction with AT\B2 or AT\B5. Other AT\Bn settings have no parity.
Figure 2. Asychronous UART Serial Interface Timing Diagram
2.2.3.2. Autobaud
When set in UART interface mode, the ISOmodem includes an automatic baud rate detection feature that allows
the host to start transmitting data at any standard DTE rate from 300 bps to 307.2 kbps. This feature is enabled by
default. When autobaud is enabled, it continually adjusts the baud rate, and the ISOmodem always echoes result
codes at the same baud rate as the most recently received character from the host. Autobaud can be turned off
using AT commands \T0 through \T15, and \T17. Host software should disable autobaud operation once the DTE
rate has been established. This prevents transients on TXD to cause inadvertent baud rate changes.
Autobaud is off when dialing, answering, and in data mode. When autobaud mode is off, the baud rate is set to the
most recently-active baud rate prior to entering one of these states. When autobaud mode is on, autoparity is
performed when either “at” or “AT” is detected. Autoparity detects the formats listed in Table 19.
Table 18. DTE Rates
Ideal DTE Rate (bps)
Actual DTE Rate (bps)
Approximate Error(%)
300
300
600
600
1200
1200
2400
2400
7200
7202
0.01
9600
9600
12000
12003
0.02
14400
14400
19200
19200
38400
38400
57600
57488
0.2
115200
115651
0.4
230400
228613 0.8
245760
245760
307200
307200
D1
D0
D2
D3
D4
D5
D6
D7
START
BIT
MARK
STOP
BIT
BIT TIMES
BIT SAMPLING
SPACE
D1
D0
D2
D3
D4
D5
D6
D7
START
BIT
MARK
STOP
BIT
BIT TIMES
BIT SAMPLING
SPACE
D8
Содержание Si2404
Страница 2: ...AN93 2 Rev 1 4 ...
Страница 27: ...AN93 Rev 1 4 27 Figure 7 Parallel Interface Read Timing Figure 8 Parallel Interface Write Timing ...
Страница 200: ...AN93 200 Rev 1 4 Figure 31 TAM Handset and Speakerphone Voice Paths ...
Страница 201: ...AN93 Rev 1 4 201 Figure 32 Si3000 Codec Gain and Signal Selection Options ...
Страница 290: ...AN93 290 Rev 1 4 Figure 57 256 Band Spectral Display Figure 58 2048 Band Spectral Display ...
Страница 305: ...AN93 Rev 1 4 305 Figure 76 Parallel or SPI Port Interrupt Service Flowchart ...