A processor recognizes an address byte differently, depending on the multiprocessor mode used. For example:
- The idle-line mode (Section 30.8) leaves a quiet space before the address byte.
This mode does not have an extra address/data bit
and is more efficient than the address-bit mode
for handling blocks that contain more than
10 bytes of data. The idle-line mode must be used
for typical non-multiprocessor SCI
communication.
- The address-bit mode (Section 30.9) adds an extra bit (that is, an address bit)
into every byte to distinguish addresses from
data. This mode is more efficient in handling many
small blocks of data because, unlike the idle
mode, this mode does not wait between blocks of
data. However, at a high transmit speed, the
program is not fast enough to avoid a 10-bit idle
in the transmission stream.