UART signals

AN3123

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Doc ID 16862 Rev 2

In SPEAr300, the device offers several different PL_GPIO sharing modes. Different

blocks/IPs are available in different configuration modes.

This has an effect on the above mentioned UART signals also. Not all SPEAR300 UART

signals in Table 3 are available in all configurations.

This is because for many applications UART is used in NULL modem mode and only

UART_RX & UART_TX are sufficient.

There are 13 possible UART configurations in SPEAr300 which can be selected by RAS

control register 2.

In configuration 1 & configuration 2, the UART with modem control lines is available.

In configurations 3 to 13, the UART without modem control lines is available (see Table 6).

Note:

On PL_GPIO[3] and PL_GPIO[2] UART_RX and UART_TX are multiplexed with external

memory controller (FSMC) signals /E3 and /E4 respectively.

2.3

SPEAr310

In SPEAr310 the external pin connections of UART1 are the same as in SPEAr300.

You can configure the device to have either

●

up to 6 UARTs without modem control lines or

●

1 UART with modem control lines.

Refer to Table 3.

Table 5.

UART configurations for SPEAr300

Signal

Configuration 1

Configuration 2

Configurations 3 to 13

PL_GPIO[42]

UART_DTR

UART_DTR

-

PL_GPIO[41]

UART_RI

UART_RI

-

PL_GPIO[40]

UART_DSR

UART_DSR

-

PL_GPIO[39]

UART_DCD

UART_DCD

-

PL_GPIO[38]

UART_CTS

UART_CTS

-

PL_GPIO[37]

UART_RTS

UART_RTS

-

PL_GPIO[3]

UART_RX

UART_RX

UART_RX

PL_GPIO[2]

UART_TX

UART_TX

UART_TX