HDQ and 1-Wire Protocols
7-193
MPU Public Peripherals
7.15.1.5
Status Flags
The status flags are provided in the status register, which contains status flags
from the transmitter, the receiver, and the presence detect logic.
The presence condition detected status flag is contained in the status register.
This is valid only in 1-Wire mode. It is cleared when the host sends an initializa-
tion pulse and then is set to 1 if a pulse is received; otherwise it stays cleared
at 0.
7.15.1.6
Interrupts
The following interrupt status is provided by the module:
-
Transmitter complete
A write of one byte was completed. Successful or unsuccessful comple-
tion is not indicated, because there is no acknowledge from the slave in
either HDQ or 1-Wire mode. Cleared at beginning of write command.
-
Read complete
Indicates successful completion of a byte read in both modes. Cleared at
beginning of read command.
-
Presence detect/time-out
J
In 1-Wire mode, it indicates that it is now valid to check the presence
detect received bit. Cleared at beginning of initialization sequence.
J
In HDQ mode, it indicates that after a read command was issued by
the host, the slave did not pull the line low within specified time. In HDQ
mode, bit is cleared at beginning of read command.
Only one interrupt is generated to the MPU, based on any of the above inter-
rupt status conditions. A read to the interrupt status register clears all the status
bits that have been set.
The interrupt can be masked by setting the appropriate bit in the control and
status register.
A read of the interrupt status register clears the interrupt. If there is a pending
interrupt the interrupt line stays low and no low-high-low transition is created.
The interrupt therefore must be handled as a level interrupt (where a low-going
edge is not needed) in an upstream interrupt handler (or processor).