AN93
Rev. 1.4
135
Figure 29. +++ Escape Timing
5.9.2. “9th Bit” Escape
The “9th Bit” escape mode feature is enabled by sending the AT\B6 command through autobaud, which detects a
9th bit space as “9th bit” escape mode. If this escape method is selected, a 1 detected on the ninth bit in a data
word returns the modem to the command mode. The 9th bit is ignored when the modem is in the command mode.
Timing for this escape sequence is illustrated in Figure 30.
Figure 30. “9th Bit” Escape Timing
5.9.3. “Escape Pin” Escape
The “escape pin is controlled by U70 [15] (HES). This bit is 0 by default, which disables the escape pin, ESC. If
HES is set to a 1, a high level on the ESC pin causes the modem to transition to the on-line command mode. The
ESC pin status is polled by the processor, and there is a latency before OK is received and the modem is in
command mode. The escape pin must be kept active until OK is received. In parallel or SPI interface mode, the
function of the escape pin is replaced by bit 2 in Hardware Interface Register 1, described in "2.2.4.2. Hardware
Interface Register 1" on page 25. Setting that bit high causes the modem to escape to the command mode.
+++
Leading Guard
Tim e
Trailing Guard
Tim e
Guard Tim e = S12 (20 m sec units)
Default Guard Tim e S12 = 50 (1.0 sec)
Guard Tim e Range = 10–255 (0.2–5.1 sec)
UART Tim ing for M odem Transm it Path (9N1 M ode with 9th Bit Escape)
D0
D1
D2
D3
D4
D5
D6
ESC
D7
Stop
Start
CTS
TX
t
RTS
t
CTH
9-Bit Data
Mode
Summary of Contents for Si2404
Page 2: ...AN93 2 Rev 1 4 ...
Page 200: ...AN93 200 Rev 1 4 Figure 31 TAM Handset and Speakerphone Voice Paths ...
Page 201: ...AN93 Rev 1 4 201 Figure 32 Si3000 Codec Gain and Signal Selection Options ...
Page 290: ...AN93 290 Rev 1 4 Figure 57 256 Band Spectral Display Figure 58 2048 Band Spectral Display ...
Page 305: ...AN93 Rev 1 4 305 Figure 76 Parallel or SPI Port Interrupt Service Flowchart ...