Modem status flags. These masks are used to access the modem status register. Whenever one of the first four bits in the modem status register changes state a modem status interrupt is generated.
| Symbol | Value | Description |
|---|---|---|
HHD_SERIAL_MSR_DCTS | 0x00000001 | This bit is the delta clear to send. It is used to indicate that the clear to send bit (in this register) has changed since this register was last read by the CPU. |
HHD_SERIAL_MSR_DDSR | 0x00000002 | This bit is the delta data set ready. It is used to indicate that the data set ready bit (in this register) has changed since this register was last read by the CPU. |
HHD_SERIAL_MSR_TERI | 0x00000004 | This is the trailing edge ring indicator. It is used to indicate that the ring indicator input has changed from a low to high state. |
HHD_SERIAL_MSR_DDCD | 0x00000008 | This bit is the delta data carrier detect. It is used to indicate that the data carrier bit (in this register) has changed since this register was last read by the CPU. |
HHD_SERIAL_MSR_CTS | 0x00000010 | This bit contains the (complemented) state of the clear to send (CTS) line. |
HHD_SERIAL_MSR_DSR | 0x00000020 | This bit contains the (complemented) state of the data set ready (DSR) line. |
HHD_SERIAL_MSR_RI | 0x00000040 | This bit contains the (complemented) state of the ring indicator (RI) line. |
HHD_SERIAL_MSR_DCD | 0x00000080 | This bit contains the (complemented) state of the data carrier detect (DCD) line. |