Lexicon MC-12HD - Getting Started

Lexicon MC-12HD Serial Communications Protocol
5 Physical Layer
5.1 DB-9 RS232 Connector
Note: The wiring requirements for a 9 pin to 9 pin serial connection are a male to female straight through
cable.
5.2 Serial Port Driver
MC-12HD serial port has been setup to operate as follows:
Operating Mode: Full Duplex
Baud rate: 19.2K baud
Data Size: 8 bits (1 byte)
Parity: Odd
Stop Bits: 1
Hardware Handshaking: None
5.3 Errors
The MC-12HD will detect parity, framing and data overrun errors. If any physical layer errors are
detected, the complete packet is corrupted and the MC-12HD will reset the transaction and begin to look
for a start of packet byte.
5.4 Receive Buffer
The MC-12HD has an internal receive buffer. The buffer is 256 Bytes and will transmit a NAK packet with
an error code of DC_ERR_BUFFER_FULL to the HOST if the buffer is full. If the buffer is full, all data
transmitted to the MC-12HD will be ignored, therefore making the currently transmitted packet, if partially
transmitted, invalid.
5.5 Hardware Verification
This test verifies the RS232 ports are working by comparing the transmitted signal (at pin 2) to the
received signal (at pin 3). The MC-12HD transmits a known test signal just following a power up. The MC-
12HD monitors the serial port receivers while transmitting the test signal. If the signals are the same, the
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