PD72042B_15 Datasheet, PDF (44/92 Pages) Renesas Technology Corp – LSI DEVICE FOR Inter Equipment BusTM (IEBusTM) PROTOCOL CONTROL

µPD72042B
RDR1
RDR2
Reception data register
Address : 0010B (2H) (RDR1)
0011B (3H) (RDR2)
Read/write : Read
When reset : 00H
The RDR1 and RDR2 registers are used to hold the number of bytes of reception data stored in RBF for each frame
received during master, slave, or broadcast reception.
b7
b0
Number of bytes of master reception data
RDR1
b7
b0
Number of bytes of slave or broadcast reception data
RDR2
[RDR1]
RDR1 indicates the number of bytes of data set in RBF by a communication frame during master reception. One
of the following values is set in RDR1:
• When master communication is requested (COMC = 1000 or 1001) : RDR1 = 0
• When master reception is started (MARC = 0100)
: RDR1 = 3
• Each time one byte of data is received
: RDR1 is incremented by 1.
[RDR2]
RDR2 indicates the number of bytes of data set in RBF by a communication frame in slave reception or broadcast
reception. One of the following values is set in RDR2:
• When slave reception is started (SLRC = 0100)
: RDR2 = 3
• When broadcast reception is started (SLRC = 1000) : RDR2 = 3
• Each time one byte of data is received
: RDR2 is incremented by 1.
• Example of RDR2 setting
Communication
frame
Data-
Control bits P A length bits P A Data P A Data P A
F
00
10
1 0 01
10
02
10
RDR2
N^Note + 3
3
4
5
Note N: Number of bytes of data received with the previous communication frame
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Data Sheet S13990EJ3V0DS