Freescale Semiconductor M9328MX21ADSE user manual UART/RS-232 Connectors, UART1 Connector

Support Information

3.4UART/RS-232 Connectors

This section describes the DB9 RS-232 serial interface connectors on the ADS. Each serial interface is controlled by a UART that is either inside the i.MX21 processor or part of an external device.

3.4.1UART1 Connector

Connector P1 connects to the UART1 pins of the i.MX21 MCU. UART1 is the primary functionality of the pins. This female DB9 connector is configured for RS-232 DCE operation. Figure 3-5shows pin assignments and Table 3-5provides signal descriptions for the connector.

G

N

D

D

T

R

R

X

D

T

X

D

C

D

5

4

3

2

1

	9		8		7
I		T	S		T	S
R	C			R

P1

	6
D	S	R

			Figure 3-5. Connector P1 (UART1) DCE Pin Assignments
			Table 3-5. Connector P1 (UART1) DCE Signal Descriptions
Pin(s)	Signal		Description
1		CD	CARRIER DETECT — RS-232 output signal, pulled active positive
2		TXD	TRANSMITTED DATA — RS-232 serial data output signal
3	RXD		RECEIVED DATA — RS-232 serial data input signal
4	DTR		DATA TERMINAL READY — RS-232 input signal, the logic level signal is available at TP8
5	GND		GROUND
6	DSR		DATA SET READY — RS-232 output signal, pulled active positive
7		RTS	READY TO SEND — RS-232 input signal, active positive
8		CTS	CLEAR TO SEND — RS-232 output signal, active positive
9		RI	RING INDICATOR — RS-232 output signal, forced inactive negative

	M9328MX21ADSE User’s Manual, Rev. A
3-18	Freescale Semiconductor