phyCORE-OMAP44xx
Part II: PCM-959/phyCORE-OMAP44xx Carrier Board
L-760e_1 © PHYTEC Messtechnik GmbH 2012
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2.1.3.3.1 Connectivity to UART 1 (TTL)
The TTL level signals of UART1 extend directly from the phyCORE-Connector X22 (pins X22C10 and X22D10) to
the expansion connector X5. UART1 of the OMAP44xx is not further used on the carrier board.
The following table shows the location of the signals on the expansion connector.
2.1.3.3.2 Connectivity to UART 2 (RS-232)
The bottom DB-9 connector of the Dual-Port Connector P1 provides the UART2 signals of the OMAP44xx at
RS-232 level. A MAX3380E RS-232 transceiver at U2 converts the TTL level signals from the phyCORE-OMAP44xx
to RS-232 level signals. To protect the phyCORE-OMAP44xx a level shifter and a quad-channel isolator at U22
isolate the transceiver from the phyCORE. The interface is 5-wire including the signals RTS and CTS for hardware
flow control.
The MAX3380E transceiver offers different operation modes including Maxim's AutoShutdown Plus™ feature to
automatically enter a 1 μA shutdown mode. In AutoShutdown Plus™ mode the device shuts down the on-chip
power supply and drivers when it does not sense a valid signal transition for 30 seconds on either the receiver
or transmitter inputs. The signal inputs FORCEON and /FORCEOFF together with the /INVALID output signal
control the different operation states of the MAX3380, as can be seen in
. Jumpers J3, J4 and J8, as well
as resistors R25 and R26 allow to configure the MAX3380 transceiver for the various operation modes.
shows the required settings.
2.1.3.3.3 Connectivity to UART 3 (RS-232)
The top DB-9 connector of the Dual-Port Connector P1 provides the UART3 signals of the OMAP44xx at RS-232
level. The interface is 5-wire including the signals RTS and CTS for hardware flow control. This RS-232 interface
is hard-wired and no jumpers must be configured for proper operation, as the TTL level signals from the
OMAP44xx are converted to RS-232 level on the phyCORE-OMAP44xx (see also
UART3 of the phyCORE-OMAP44xx is used as monitoring/debug interface.
Pin #
Signal
I/O
SL
Description
X5C35
X_UART1_TX
O
VCC_1V8_IO
Serial transmit signal of UART 1
X5C36
X_UART1_RX
I
1.8 V
Serial receive signal of UART 1
Table 47:
Mapping of the UART1 Signals on the Expansion Connector (X5)
Note:
The RS-232 transceiver on the phyCORE-OMAP44xx is configured to operate in AutoShutdown mode, which
means that it shuts down if invalid signals are detected (Please refer to
and the datasheet of the
MAX3380E/MAX3381E for more information).
