I2C Bus Controller
I2C Bus Interface Registers
MN102H75K/F75K/85K/F85K LSI User Manual Panasonic Semiconductor Development Company
305
Panasonic
I2CDREC: I2C Reception Data Register x’007E42’
The I2CDREC register contains the status bits for monitoring the device
and the reception data. I2CDREC is a read-only register.
MODE[1:0]: I2C device mode
This field indicates which I2C mode the microcontroller is in. MODE1
indicates slave or master, and MODE0 indicates receiver or transmitter. If
the microcontroller loses an arbitration or if a stop condition occurs, the
hardware clears MODE[1:0] to b’00’.
00:Slave receiver 10: Master receiver
01:Slave transmitter 11:Master transmitter
STS: Stop condition at slave receiver
Set to 1 when a stop condition is detected while the microcontroller is in
slave receiver mode.
LRB: Last received bit.
Stores the last serial data bit received. LRB normally indicates the ACK
cycle data.
AAS: Addressed as slave
Set to 1 when the slave address on the bus matches the contents of the
address register or matches the general address (x’00’). AAS resets after a
read from the I2CDREC register.
LAB: Lost arbitration bit
Set to 1 when the microcontroller loses a bus arbitration. LAB resets when
I2CDTRM indicates a start condition (STA = 1).
BB: Bus busy bit
A start condition on the bus sets this flag to 0, and a stop condition resets it
to 1. The microcontroller considers the bus to be busy as long as BB = 0.
D[7:0]: Received data
The serial data received from the I2C bus is shifted into this field MSB
first.
I2CMYAD: I2C Self Address Register x’007E44’
A[6:0]: Microcontroller address
This register is formed from a 7-bit field address latch. It holds the micro-
controller’s own address, used for a compare when the microcontroller is
addressed as a slave. When a match occurs, AAS is set to 1.
Bit:1514131211109876543210
MODE
1MODE
0STSLRBAASLABBBD7D6D5D4D3D2D1D0
Reset:0000000100000000
R/W:RRRRRRRRRRRRRRRR
Bit:1514131211109876543210
—————————A6A5A4A3A2A1A0
Reset:0000000000000000
R/W:RRRRRRRRRR/WR/WR/WR/WR/WR/WR/W