Z02215
Single-Chip Modem
12
Table 2.
Status Register (Continued)
Default
Value
0
Bit No.
Bit 4
Mnemonic R/W
RBRK
R/W
Description
Break signal sent to the host. The Z02215 sets
this bit to 1 to indicate that a line break is
transmitted to the host. The Z02215 resets this
bit to 0 when the line break condition is ended.
DCD signal sent from the Z02215.
1鈥揂ctive
0鈥揑nactive
Transmit Register Interrupt Enable. When this
bit is 1, the Z02215 drives the HIRQ pin Low
when TRE is 1
Receive Register Interrupt Enable. When this bit
is 1, the Z02215 drives the HIRQ pin Low when
RRF is 1.
Bit 5
DCD
R/W
1
Bit 6
TRIE
R/W
0
Bit 7
RRIE
R/W
0
Modem States of Operation
The Modem Controller software features several different states of operation.
DIALING
IDLE
RETRAIN
HANDSHAKE
COMMAND
ON-LINE
Figure 4.
Modem State Diagram
PRELIMINARY
PS001901-MOD0300