PSB21373HV11XT Infineon Technologies, PSB21373HV11XT Datasheet - Page 51

• Manufacturer Part Number: PSB21373HV11XT
• Manufacturer: Infineon Technologies
• Type: PCMr

Specifications of PSB21373HV11XT

• Number Of Channels: 1
• Number Of Adc's: 1
• Number Of Dac's: 1
• Number Of Adc Inputs: 1
• Pin Count: 44
• Mounting: Surface Mount
• Lead Free Status / RoHS Status: Compliant

PSB 21373
Before starting a transmission, the microcontroller should verify that the transmitter is
inactive, i.e. that a possible previous transmission has been terminated. This is indicated
by a ’0’ in the MONITOR Channel Active MAC status bit.
After having written the MONITOR Data Transmit (MOX) register, the microcontroller
sets the MONITOR Transmit Control bit MXC to ’1’. This enables the MX bit to go active
(0), indicating the presence of valid MONITOR data (contents of MOX) in the
corresponding frame. As a result, the receiving device stores the MONITOR byte in its
MONITOR Receive MOR register and generates an MDR interrupt status (MRE must be
’1’).
Alerted by the MDR interrupt, the microcontroller reads the MONITOR Receive (MOR)
register. When it is ready to accept data (e.g. based on the value in MOR, which in a
point-to-multipoint application might be the address of the destination device), it sets the
MR control bit MRC to ’1’ to enable the receiver to store succeeding MONITOR channel
bytes and acknowledge them according to the MONITOR channel protocol. In addition,
it enables other MONITOR channel interrupts by setting MONITOR Interrupt Enable
(MIE) to ’1’.
As a result, the first MONITOR byte is acknowledged by the receiving device setting the
MR bit to ’0’. This causes a MONITOR Data Acknowledge MDA interrupt status at the
transmitter.
A new MONITOR data byte can now be written by the microcontroller in MOX. The MX
bit is still in the active (0) state. The transmitter indicates a new byte in the MONITOR
channel by returning the MX bit active after sending it once in the inactive state. As a
result, the receiver stores the MONITOR byte in MOR and generates a new MDR
interrupt status. When the microcontroller has read the MOR register, the receiver
acknowledges the data by returning the MR bit active after sending it once in the inactive
state. This in turn causes the transmitter to generate an MDA interrupt status.
This "MDA interrupt – write data – MDR interrupt – read data – MDA interrupt"
handshake is repeated as long as the transmitter has data to send.
When the last byte has been acknowledged by the receiver (MDA interrupt status), the
microcontroller sets the MONITOR Transmit Control bit MXC to ’0’. This enforces an
inactive (’1’) state in the MX bit. Two frames of MX inactive signifies the end of a
message. Thus, a MONITOR Channel End of Reception MER interrupt status is
generated by the receiver when the MX bit is received in the inactive state in two
consecutive frames. As a result, the microcontroller sets the MR control bit MRC to 0,
which in turn enforces an inactive state in the MR bit. This marks the end of the
transmission, making the MONITOR Channel Active MAC bit return to ’0’.
During a transmission process, it is possible for the receiver to ask a transmission to be
aborted by sending an inactive MR bit value in two consecutive frames. This is effected
by the microcontroller writing the MR control bit MRC to ’0’. An aborted transmission is
indicated by a MONITOR Channel Data Abort MAB interrupt status at the transmitter.
The MONITOR transfer protocol rules are summarized in the following section
Data Sheet
51
2002-05-13