M37212 Mitsubishi, M37212 Datasheet - Page 42

• Manufacturer Part Number: M37212
• Description: SINGLE-CHIP 8-BIT CMOS MICROCOMPUTER for VOLTAGE SYNTHESIZER
• Manufacturer: Mitsubishi

Fig. 8.6.12 Address Data Communication Format
8.6.12 Precautions when using multi-master
(1) Read-modify-write instruction
The precautions when the raead-modify-write instruction such as SEB,
CLB etc. is executed for each register of the multi-master I
interface are described below.
•I
•I
•I
•I
•I
42
2
When executing the read-modify-write instruction for this register
during transfer, data may become a value not intended.
2
When the read-modify-write instruction is executed for this register
at detecting the STOP condition, data may become a value not
intended. It is because hardware changes the read/write bit (RBW)
at the above timing.
2
Do not execute the read-modify-write instruction for this register
because all bits of this register are changed by hardware.
2
When the read-modify-write instruction is executed for this register
at detecting the START condition or at completing the byte transfer,
data may become a value not intended. Because hardware changes
the bit counter (BC0–BC2) at the above timing.
2
The read-modify-write instruction can be executed for this register.
C data shift register (S0)
C address register (S0D)
C status register (S1)
C control register (S1D)
C clock control register (S2)
I
2
C-BUS interface
( 1 ) A m a s t e r - t r a n s m i t t e r t r a n s m i t s d a t a t o a s l a v e - r e c e i v e r
( 2 ) A m a s t e r - r e c e i v e r r e c e i v e s d a t a f r o m a s l a v e - t r a n s m i t t e r
( 3 ) A m a s t e r - t r a n s m i t t e r t r a n s m i t s d a t a t o a s l a v e - r e c e i v e r w i t h a 1 0 - b i t a d d r e s s
( 4 ) A m a s t e r - r e c e i v e r r e c e i v e s d a t a f r o m a s l a v e - t r a n s m i t t e r w i t h a 1 0 - b i t a d d r e s s
S : S T A R T c o n d i t i o n
A : A C K b i t
S r : R e s t a r t c o n d i t i o n
S
S
S
S
S l a v e a d d r e s s
S l a v e a d d r e s s
S l a v e a d d r e s s
1 s t 7 b i t s
S l a v e a d d r e s s
1 s t 7 b i t s
7 b i t s
7 b i t s
7 b i t s
7 b i t s
R / W
R / W
R / W
R / W
“ 0 ”
“ 1 ”
“ 0 ”
“ 0 ”
M37212M4/M8–XXXSP, M37212M6–XXXSP/FP
A
A
A
A
P : S T O P c o n d i t i o n
R / W : R e a d / W r i t e b i t
______
1 t o 8 b i t s
1 t o 8 b i t s
S l a v e a d d r e s s
2 n d b y t e
S l a v e a d d r e s s
2 n d b y t e
D a t a
D a t a
SINGLE-CHIP 8-BIT CMOS MICROCOMPUTER for VOLTAGE SYNTHESIZER
8 b i t s
8 b i t s
A
A
2
C-BUS
1 t o 8 b i t s
1 t o 8 b i t s
D a t a
D a t a
A
A
1 t o 8 b i t s
D a t a
S r
A / A
A
(2) START condition generating procedure us-
BUSFREE:
BUSBUSY:
S l a v e a d d r e s s
1 s t 7 b i t s
F r o m m a s t e r t o s l a v e
F r o m s l a v e t o m a s t e r
Procedure example (The necessary conditions of the generating
Use “STA,” “STX” or “STY” of the zero page addressing instruction
Use “LDM” instruction for setting trigger of START condition gener-
Write the slave address value of above
Disable interrupts during the following three process steps:
procedure are described as the following
for writing the slave address value to the I
ating.
condition generating of above
procedure example.
• BB flag confirming
• Writing of slave address value
• Trigger of START condition generating
When the condition of the BB flag is bus busy, enable interrupts
immediately.
7 b i t s
P
P
A
ing multi-master
LDA
SEI
BBS 5,S1,BUSBUSY (BB flag confirming and branch process)
STA S0
LDM #$F0, S1
CLI
CLI
1 t o 8 b i t s
D a t a
R / W
“ 1 ”
•
•
—
•
•
•
•
A / A
with ON-SCREEN DISPLAY CONTROLLER
1 t o 8 b i t s
D a t a
MITSUBISHI MICROCOMPUTERS
P
A
(Taking out of slave address value)
(Interrupt disabled)
(Writing of slave address value)
(Trigger of START condition generating)
(Interrupt enabled)
(Interrupt enabled)
1 t o 8 b i t s
M37212EFSP/FP
D a t a
continuously shown the above
A
and set trigger of START
2
C data shift register.
to
P
).
Rev. 1.0