GBS Elektronik MCA-527 - Manual (Page 20)

MCA527
2.2.11 Extension Port
The extension port is only available on the MCA527, the MCA527L and the MCA527OEM
are not equipped with this functionality. This port extends the possibilities of the MCA
enormously. Different external devices, such as GPS receivers or neutron counters, can
be attached to the MCA527 by a 9 pin Lemo connector (Table 6). Figure 7 shows the
block diagram. Currently the basic functionality is implemented in the firmware but no
application program takes advantage of it.
The extension port consist of six independent parts labeled A to F. Part A is a true RS232
interface which can operate at speeds up to 1MBaud. To save power, the transceiver is
disabled by default. Part B is a 3.3V digital output with output enable. It can be used as
general purpose output or as TTL-UART TxD. Part C is a 3.3V digital input which is 5V
tolerant. It can be used as general purpose input or as TTL-UART RxD. The TTL-UART
can be operated at speeds up to 3MBaud. Part D is an additional 3.3V digital output with
output enable. It can be used as general purpose output or as timer output for pulse
generation. Part E is a further 5V tolerant 3.3V digital input which can be used as general
purpose input or as fast counter. To supply external devices with power, a 5V converter is
also part of the extension port (F). It can be loaded with up to 100mA. To save power, it is
disabled by default.
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Figure 7: Block diagram of the extension port. This functions are only supported by the
MCA527.