UPD72042BGT NEC [NEC], UPD72042BGT Datasheet - Page 32

• Manufacturer Part Number: UPD72042BGT
• Description: LSI DEVICE FOR Inter Equipment Bus (IEBus) PROTOCOL CONTROL
• Manufacturer: NEC [NEC]

control, or optional function setting.
processes the data set in CMR, CEX is set to 0.
(1) When bit 7 (MSB) of CMR is 0
[LOCK]: Lock state setting command
[BUFC]: Transmission/reception buffer control command
[COMC]: Communication control command
32
CMR is a one-byte write register used to set a command for communication control, transmission/reception buffer
When data is set in CMR from the microcomputer, CEX of the FLG register is set to 1. When the PD72042B
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 : The value representing the lock state (0001 for locked or 0000 for not-locked) and lock address are output
0 : The contents of LOR1 and LOR2 remain as is.
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
0000: Communication operation remains as is.
0001: The locked state is cancelled.
1000: Master communication is requested
1001: Master communication is requested, with the previous master transmission state held
1010: Master communication is aborted.
1011: Slave data transmission is requested
1100: Slave data transmission is requested, with the previous slave data transmission state held
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,
CMR
Command register
to LOR1 and LOR2. Note, however, that when 0000 (not-locked) is output, any lock address value is ignored.
cleared
or optional function setting in CMR is selected and MFC = 0, clear RBF with BUFC = 10.
Note 1
.
b7
0
LOCK
b6
b5
BUFC
Data Sheet S13990EJ3V0DS
Note 2
Note 4
b4
.
.
b3
COMC
Address
Read/write
When reset : 00000000B
b0
CMR
: 0001B (1H)
: Write
Note 3
Note 5
.
PD72042B
.