7.1 RTS/CTS handshake
Transmission of RTS, combined with reception of CTS, allows for hardware handshaking (data flow control) between the UART and the external device. RTS is transmitted on AUXOUT by connecting pins 4 and 5 of the jumper pack. CTS is received on AUXIN by connecting pins 1 and 2 of the jumper pack. If RTS/CTS handshaking is not desired, the RTS output can be looped back to the CTS input by connecting pins 1 and 4 of the jumper pack. Figure 17 shows how to select the RTS/CTS mode.
AUXOUT |
| XCLK | AUXOUT |
RTS |
|
| RTS |
5 | 6 | 6 |
|
1 | 2 | 3 |
CTS |
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| CTS |
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AUXIN |
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| RCLK | AUXIN | ||
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Transmit RTS on AUXOUT
Receive CTS on AUXIN
XCLK
5 | 5 | 6 |
1 | 2 | 3 |
RCLK
Loopback RTS to CTS
Figure 17 --- RTS/CTS selection on J5, J7
7.2 RCLK
This is the clock signal used by the receiver portion of the UART. It is generally provided by connecting it to the UART's own transmit clock output (XCLK). This is done by connecting pins 3 and 6 of the jumper pack. If desired, RCLK can be received from an external source over the AUXIN line by connecting pins 2 and 3 of the jumper pack. Figure 18 shows how to select the RCLK mode.
AUXOUT RTS
XCLK AUXOUT RTS
XCLK
4 | 5 | 7 |
|
1 | 2 | 3 |
|
CTS |
|
| CTS |
AUXIN |
| RCLK | AUXIN |
Loopback XCLK to RCLK
4 5 6
1 | 2 | 3 |
RCLK
Receive RCLK on AUXIN