M38867E8AHP MITSUBISHI [Mitsubishi Electric Semiconductor], M38867E8AHP Datasheet - Page 45

• Manufacturer Part Number: M38867E8AHP
• Description: SINGLE-CHIP 8-BIT CMOS MICROCOMPUTER??
• Manufacturer: MITSUBISHI [Mitsubishi Electric Semiconductor]

•Bit 6: Communication mode specification bit (transfer direc-
This bit decides a direction of transfer for data communication.
When this bit is “0,” the reception mode is selected and the data of
a transmitting device is received. When the bit is “1,” the transmis-
sion mode is selected and address data and control data are
output onto the S
the S
This bit is set/reset by software and hardware. About set/reset by
hardware is described below. This bit is set to “1” by hardware
when all the following conditions are satisfied:
• When ALS is “0”
• In the slave reception mode or the slave transmission mode
• When the R/W bit reception is “1”
This bit is set to “0” in one of the following conditions:
• When arbitration lost is detected.
• When a STOP condition is detected.
• When writing “1” to this bit by software is invalid by the START
• With MST = “0” and when a START condition is detected.
• With MST = “0” and when ACK non-return is detected.
• At reset
•Bit 7: Communication mode specification bit (master/slave
This bit is used for master/slave specification for data communica-
tion. When this bit is “0,” the slave is specified, so that a START
condition and a STOP condition generated by the master are re-
ceived, and data communication is performed in synchronization
with the clock generated by the master. When this bit is “1,” the
master is specified and a START condition and a STOP condition
are generated. Additionally, the clocks required for data communi-
cation are generated on the SCL.
This bit is set to “0” in one of the following conditions.
• Immediately after completion of 1-byte data transfer when arbi-
• When a STOP condition is detected.
• Writing “1” to this bit by software is invalid by the START condi-
• At reset
Note: START condition duplication preventing function
condition duplication preventing function (Note).
tration lost is detected
tion duplication preventing function (Note).
CL
The MST, TRX, and BB bits is set to “1” at the same time after con-
firming that the BB flag is “0” in the procedure of a START condition
occurrence. However, when a START condition by another master
device occurs and the BB flag is set to “1” immediately after the con-
tents of the BB flag is confirmed, the START condition duplication
preventing function makes the writing to the MST and TRX bits in-
valid. The duplication preventing function becomes valid from the
rising of the BB flag to reception completion of slave address.
tion specification bit: TRX)
specification bit: MST)
.
DA
in synchronization with the clock generated on
Fig. 40 Interrupt request signal generating timing
Fig. 39 Structure of I
M S T
b 7
N o t e : T h e s e b i t a n d f l a g s c a n b e r e a d o u t b u t c a n n o t
I
2
C I R Q
T R X B B P I N A L A A S A D 0 L R B
P I N
S
C L
b e w r i t t e n .
W r i t e “ 0 ” t o t h e s e b i t s a t w r i t i n g .
SINGLE-CHIP 8-BIT CMOS MICROCOMPUTER
MITSUBISHI MICROCOMPUTERS
2
C status register
b 0
I
( S 1 : a d d r e s s 0 0 1 4
L a s t r e c e i v e b i t ( N o t e )
G e n e r a l c a l l d e t e c t i n g f l a g
( N o t e )
S l a v e a d d r e s s c o m p a r i s o n f l a g
( N o t e )
A r b i t r a t i o n l o s t d e t e c t i n g f l a g
( N o t e )
I
r e q u e s t b i t
B u s b u s y f l a g
C o m m u n i c a t i o n m o d e
s p e c i f i c a t i o n b i t s
2
2
C s t a t u s r e g i s t e r
C - B U S i n t e r f a c e i n t e r r u p t
0 : L a s t b i t = “ 0 ”
1 : L a s t b i t = “ 1 ”
0 : N o g e n e r a l c a l l d e t e c t e d
1 : G e n e r a l c a l l d e t e c t e d
0 : A d d r e s s d i s a g r e e m e n t
1 : A d d r e s s a g r e e m e n t
0 : N o t d e t e c t e d
1 : D e t e c t e d
0 : B u s f r e e
1 : B u s b u s y
0 0 : S l a v e r e c e i v e m o d e
0 1 : S l a v e t r a n s m i t m o d e
1 0 : M a s t e r r e c e i v e m o d e
1 1 : M a s t e r t r a n s m i t m o d e
0 : I n t e r r u p t r e q u e s t i s s u e d
1 : N o i n t e r r u p t r e q u e s t
3886 Group
i s s u e d
1 6
)
45