PD72042B_15 Datasheet, PDF (48/92 Pages) Renesas Technology Corp – LSI DEVICE FOR Inter Equipment BusTM (IEBusTM) PROTOCOL CONTROL

µPD72042B
Table 4-2 MARC Return Codes for Master Transmission
MARC
0000
0001
0010
0011
Description
1. Meaning: Master transmission is started.
2. Occurrence condition: This return code is issued when the master address field in a communication
frame has been transmitted, and the unit has won the arbitration to become the master unit.
1. Meaning: Master transmission data is not available.
2. Occurrence condition: This return code is issued if the next transmission data is not set in TBF during
master transmission.
3. Microcomputer processing: If data consisting of one or more bytes is not set in TBF within the time
below, transmission may be terminated prior to its completion.
• Transmission data setting time: Approx. 1570 µs (mode 0)
Approx. 390 µs (mode 1)
1. Meaning: Master transmission 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 transmitted normally. In this case, the MARQ flag of the FLG register changes
from 1 to 0.
1. Meaning: Master transmission 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, the control field, or the data-length field of a communication frame (excluding the broadcast).
• When a communication is terminated prior to the transmission of as much data as the amount specified
in the data-length field of a communication frame.
(b) Master reception
Master reception is performed when the microcomputer performs the setting below.
• Master reception setting
1 In the low-order 4 bits of the MCR register, control bits (0000, 0011, 0100, 0101, 0110, or 0111) are set
for slave-to-master data transfer.
2 In COMC of the CMR register, a command (1000 or 1001) for requesting master communication is set.
Table 4-3 indicates the MARC return codes for master reception.
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Data Sheet S13990EJ3V0DS