Specifications

24 DSP56800 Hardware Interface Techniques 
Peripheral Interfaces
4.6 SCI Interface
An example of an SCI interface is that provided by the DSP56F807EVM. The EVM provides an
RS-232 interface by the use of an RS-232 level converter, (Maxim MAX3245EEAI). Refer to the
RS-232 schematic diagram in Figure 23. The RS-232 level converter transitions the SCI UART’s
3.3V signal levels to RS-232 compatible signal levels and connects to the host’s serial port via
connector P3. Flow control is not provided, but could be implemented using uncommitted GPIO
signals. The pinout of connector P3 is listed in Table 7. The RS-232 level converter/transceiver can be
disabled by placing a jumper at JG1.
Figure 23. Schematic Diagram of the RS-232 Interface
.
Table 7: RS-232 Serial Connector Description
P3
Pin # Signal Pin # Signal
1 Jumper to 6 & 4 6 Jumper to 1 & 4
2 TXD 7 Jumper to 8
3 RXD 8 Jumper to 7
4 Jumper to 1 & 6 9 N/C
5GND
DSP56F807
RS-232
Level Converter
Interface
TXDO
RXDO
R1in
T1out
T1in
R1out
FORCEOFF
JG1
1
2
6
3
2
7
8
4
5
x
1
9
+3.3V
Jumper Removed:
Enable RS-232
Jumper Pin 1-2:
Disable RS-232
Frees
cale Semiconductor,
I
Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
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