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PD72042B_15 Datasheet, PDF (34/92 Pages) Renesas Technology Corp – LSI DEVICE FOR Inter Equipment BusTM (IEBusTM) PROTOCOL CONTROL
µPD72042B
CMR
Command register
Address : 0001B (1H)
Read/write : Write
When reset : 00000000B
CMR is a one-byte write register used to set a command for communication control, transmission/reception buffer
control, or optional function setting.
When data is set in CMR from the microcomputer, CEX of the FLG register is set to 1. When the µPD72042B
processes the data set in CMR, CEX is set to 0.
After the microcomputer checks that CEX of the FLG register is set to 0, new data can be set in CMR.
The following describes the data that is set in CMR.
(1) When bit 7 (MSB) of CMR is 0
b7
b6
b5
b4
b3
0 LOCK
BUFC
COMC
b0
CMR
[LOCK]: Lock state setting command
1 : The value representing the lock state (0001 for locked or 0000 for not-locked) and lock address are output
to LOR1 and LOR2. Note, however, that when 0000 (not-locked) is output, any lock address value is ignored.
0 : The contents of LOR1 and LOR2 remain as is.
[BUFC]: Transmission/reception buffer control command
00 : The transmission and reception buffers remain as is.
01 : The transmission buffer (TBF) is cleared.
10 : The reception buffer (RBF) is cleared.
11 : The data of the previous (latest) communication frame to be stored in the reception buffer (RBF) is
clearedNote 1.
[COMC]: Communication control command
0000: Communication operation remains as is.
0001: The locked state is cancelled.
1000: Master communication is requestedNote 2.
1001: Master communication is requested, with the previous master transmission state heldNote 3.
1010: Master communication is aborted.
1011: Slave data transmission is requestedNote 4.
1100: Slave data transmission is requested, with the previous slave data transmission state heldNote 5.
1101: Slave data transmission is aborted.
1111: Slave reception and broadcast reception are disabled.
Notes 1. If the microcomputer has already read the data for the previous (latest) communication frame from RBF,
or optional function setting in CMR is selected and MFC = 0, clear RBF with BUFC = 10.
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Data Sheet S13990EJ3V0DS