AMD Alchemy Au1550 Security Network Processor Data Book
297
UART Interfaces
30283D
9.3.3
UART Signals
The UART signals are listed in Table 9-13. For changing pin functionality please refer to the sys_pinfunc register in
Section Table 9-13. UART Signals
Signal
Input/
Output
Definition
UART0
U0TXD
O
UART0 Transmit.
U0RXD
I
UART0 Receive.
UART1
U1TXD
O
UART1 Transmit.
U1RXD
I
UART1 Receive.
U1CTS#
I
Clear to Send.
U1RTS#
O
Request to Send. Muxed with GPIO[22]. GPIO[22] is the default signal coming out of hard-
ware reset, runtime reset, and Sleep.
UART3
U3TXD
O
UART3 Transmit.
U3RXD
I
UART3 Receive.
U3CTS#
I
Clear to Send. Muxed with GPIO[9]. GPIO[9] is the default signal coming out of hardware
reset, runtime reset, and Sleep.
System Note: For systems that use the UART3 interface without the modem control sig-
nals (sys_pinfunc[UR3]=0), the modem status interrupts must be disabled
(uart3_inten[MIE]=0) to avoid false UART3 interrupts when using GPIO[9], GPIO[10],
GPIO[11], or GPIO[12] as an input.
U3DSR#
I
Data Set Ready. Muxed with GPIO[10]. GPIO[10] is the default signal coming out of hard-
ware reset, runtime reset, and Sleep.
System Note: For systems that use the UART3 interface without the modem control sig-
nals (sys_pinfunc[UR3]=0), the modem status interrupts must be disabled
(uart3_inten[MIE]=0) to avoid false UART3 interrupts when using GPIO[9], GPIO[10],
GPIO[11], or GPIO[12] as an input.
U3DCD#
I
Data Carrier Detect. Muxed with GPIO[11]. GPIO[11] is the default signal coming out of
hardware reset, runtime reset, and Sleep.
System Note: For systems that use the UART3 interface without the modem control sig-
nals (sys_pinfunc[UR3]=0), the modem status interrupts must be disabled
(uart3_inten[MIE]=0) to avoid false UART3 interrupts when using GPIO[9], GPIO[10],
GPIO[11], or GPIO[12] as an input.
U3RI#
I
Ring Indication. Muxed with GPIO[12]. GPIO[12] is the default signal coming out of hard-
ware reset, runtime reset, and Sleep.
System Note: For systems that use the UART3 interface without the modem control sig-
nals (sys_pinfunc[UR3]=0), the modem status interrupts must be disabled
(uart3_inten[MIE]=0) to avoid false UART3 interrupts when using GPIO[9], GPIO[10],
GPIO[11], or GPIO[12] as an input.
U3RTS#
O
Request to Send. Muxed with GPIO[13]. GPIO[13] is the default signal coming out of hard-
ware reset, runtime reset, and Sleep.
U3DTR#
O
Data Terminal Ready. Muxed with GPIO[14]. GPIO[14] is the default signal coming out of
hardware reset, runtime reset, and Sleep.