Comtech EF Data SDM-650B - Manual (Page 48)

Configuration SDM-650B Satellite Modem
3–6 Rev. 5
3.1.2 Remote Interface Specification
Refer to Appendix B for remote control operation information.
3.1.3 M&C Theory of Operation
The M&C module is built around the Intel 80C31 microcontroller operating at
5.5295 MHz. The microsystem is designed to support:
• 64K bytes of read-only code memory
• 64K bytes of random access data memory
Of the 64K bytes data memory, only 4K is used for RAM. The remaining address is used
for memory-mapped I/O. Memory-mapped I/O includes:
• Real time clock/memory
• 8-channel analog-to-digital converter
• External buffered bus structure for overall modem control and status gathering
The 80C31 microcontroller supports a serial asynchronous communications channel with
a maximum baud rate of 9600 bit/s using the 5.5295 MHz reference.
A rechargeable battery is employed to maintain the system real time clock and modem
configuration through power-out situations.