Sigma DE2-70 manual 5.9 RS-232 Serial Port, 5.10 PS/2 Serial Port

DE2-70 User Manual

5.9 RS-232 Serial Port

The DE2-70 board uses the ADM3202 transceiver chip and a 9-pin D-SUB connector for RS-232 communications. For detailed information on how to use the transceiver refer to the datasheet, which is available on the manufacturer’s web site, or in the Datasheet/RS232 folder on the DE2-70 System CD-ROM. Figure 5.15 shows the related schematics, and Table 5.13 lists the Cyclone II FPGA pin assignments.

	RXD	LEDR
R44	330	UART_RXD
VCC33	TXD	LEDG
R45	330	UART_TXD
		UART_RXD
		UART_RTS
		UART_TXD
		UART_CTS
		C9	1u
	VCC33	C10	1u
	BC33		C11
	0.1u		1u

12

9

11 10

1

3

4

5

2 6

C12 1u

U7
R1OUT		R1IN
R2OUT		R2IN
T1IN		T1OUT
T2IN		T2OUT
C+	ADM3202
C1-
		VCC
C2+
C2-		GND
V+
V-

13RXD

8RTS

14TXD

7CTS

16VCC33

	J2
	5
	9
	4
	8
	3
	7
	2
	6
	1
	10 11
BC32	0.1u

RS232

Figure 5.15. MAX232 (RS-232) chip schematic.

Signal Name	FPGA Pin No.	Description
UART_RXD	PIN_D21	UART Receiver
UART_TXD	PIN_E21	UART Transmitter
UART_CTS	PIN_G22	UART Clear to Send
UART_RTS	PIN_F23	UART Request to Send

Table 5.13. RS-232 pin assignments.

5.10 PS/2 Serial Port

The DE2-70 board includes a standard PS/2 interface and a connector for a PS/2 keyboard or mouse. In addition, users can use the PS/2 keyboard and mouse on the DE2-70 board simultaneously by an plug an extension PS/2 Y-Cable. Figure 5.16 shows the schematic of the PS/2 circuit. Instructions for using a PS/2 mouse or keyboard can be found by performing an appropriate search on various educational web sites. The pin assignments for the associated interface are shown in Table 5.14.

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