PD72042B_15 Datasheet, PDF (49/92 Pages) Renesas Technology Corp – LSI DEVICE FOR Inter Equipment BusTM (IEBusTM) PROTOCOL CONTROL

µPD72042B
Table 4-3 MARC Return Codes for Master Communication
MARC
0100
Description
1. Meaning: Master reception has started.
2. Occurrence condition:
1 The unit has won the arbitration to become the master unit, and a communication frame up to the
data-length field was transferred successfully.
2 When the control field is received, RBF becomes ready for reception^Note.
0101
0110
0111
After the data-length field, 0000 is set in MARC, and three-byte data consisting of a slave address,
control bits, and data-length bits is set in RBF. If RBF becomes full when this three-byte data is set,
0001 is set in MARC.
3. Microcomputer processing: Three-byte data consisting of a slave address, control bits, and data-
length bits can be read from RBF.
1. Meaning: The master reception buffer is full.
2. Occurrence condition: This return code is issued when RBF becomes full during data reception as the
master unit, and reception data cannot be set in RBF.
3. Microcomputer processing: If data consisting of one or more bytes is not read from RBF within the
time below, the one-byte data cannot be received, and the µPD72042B returns an NAK.
• Reception data read time: Approx. 1570 µs (mode 0)
Approx. 390 µs (mode 1)
1. Meaning: Master reception was terminated normally.
2. Occurrence condition: This return code is issued when as much data as the amount specified in the
data-length field has been received normally in a communication frame. In this case, the MARQ flag of
the FLG register changes from 1 to 0.
3. Microcomputer processing: Reception data can be read from RBF, and the number of bytes of
master reception data can be read from RDR1.
1. Meaning: Master reception was aborted.
2. Occurrence condition: This return code is issued in any of the following cases. In each case, the
MARQ flag of the FLG register changes from 1 to 0.
• When the unit has lost the arbitration to become the master unit.
• When a transmission is stopped because the NAK is returned from the slave unit at the end of the
slave address field or the control field of a communication frame or because the NAK is sent to the
slave unit at the end of the data-length field of a communication frame (excluding the broadcast).
• When a communication is terminated prior to the reception of as much data as the amount specified
in the data-length field of a communication frame.
3. Microcomputer processing: Reception data can be read from RBF, and the number of bytes of
master reception data can be read from RDR1.
Note See Note of Table 4-9.
Data Sheet S13990EJ3V0DS
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