10.1 DTE Configuration
The control signals that the DTE can generate are the Request To Send (RTS) and Data Terminal Ready (DTR). It can receive the signals Carrier Detect (CD), Clear to Send (CTS), and Data Set Ready (DSR). All of the control signals are controlled through channel A of the SCC, with the exception of the DSR signal, which is received on channel B.
The DTE’s transmit clock (TCLK from the SCC TRXCA pin) can be transmitted on TTCLK or received on RTCLK depending on TCKEN (D2 of the communica- tions register). The receive clock (RCLK from the SCC RTxC pins) can be received on RRCLK or can be generated on the TRxCB pin of the SCC, depend- ing on RCKEN ( D3 of the communications register). The DTE can not transmit its RCLK. Figure 4 illustrates the clock circuitry of the
Figure 2 DTE Clock Configuration
RTXCA |
(RCLK) |
RTXCB |
TRXCB |
RCKEN |
TCKEN |
RRCLK
RTCLK
TRXCA (TCLK)
TTCLK
The testing signals that the DTE can generate are the Local Loopback Test (LL) and the Remote Loopback Test (RL). These signals are can be controlled through the onboard communications register. The DTE can generate an interrupt when a Test Mode (TM) condition is received. Table 15 summarizes the signals on the DTE.
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