tmp1941af TOSHIBA Semiconductor CORPORATION, tmp1941af Datasheet - Page 290

• Manufacturer Part Number: tmp1941af
• Description: 32-bit Tx System Risc
• Manufacturer: TOSHIBA Semiconductor CORPORATION

18.7 SBI Timing
18.7.1
SCL clock frequency
Hold time for START condition
Low period of the SCL
clock
SCL clock high width
Setup time for a repeated START
condition
Data hold time
Data setup time
Setup time for STOP condition
Bus free time between STOP and
START conditions
Note 1: Different from the Philips I
Note 2: The ouptut data hold time is equal to 12x.
Note 3: The Philips I
Note 4: To operate the SBI in I
Note 5: Although THE I
Note 6: The SDA hold time from the falling edge of
the SDA signal to bridge the undefined region of the fall edge of SCL. However, the TMP1941AF SBI does not
satisfy this requirement. Also, the output buffer for SCL does not incorporate slope control of the falling
edges; therefore, the equipment manufacturer should design so that the input data hold time shown in the
table is satisfied, including tr/tf of the SCL and SDA lines.
Standard mode, the fsys frequency must be no less than 4 MHz.
obstruct the SDA and SCL lines if V
SCL varies with the fsys frequency, as
shown at left. The fsys frequency must be
determined, considering the devices
connected on the I
the I
minimum delay of 100 ns from the falling
edge of SCL, the required hold time must be
less than 100 ns; thus the fsys frequency
must be 20 MHz or larger.
Parameter
I
letter n denotes the value of n programmed into the SCK[2:0] (SCL output frequency select) field in the
SBI0CR1.
2
2
C Mode
C bus drive the SDA line within a
In the table below, the letters x and T represent the fsys and φT0 cycle periods, respectively. The
SDA
SCL
2
C-bus specification states that a device must internally provide a hold time of at least 300 ns for
S: START condition, Sr: Repeated START condition, P: STOP condition
Input
Output
Input
Output
2
C BUS SPECIFICATION from Philips states that I/O pins of Fast-mode devices must not
2
C bus. If the devices on
S
t
2
HD;STA
C Fast mode, the fsys frequency must be no less than 20 MHz. To operate the SBI in I
Symbol
t
t
t
t
t
t
t
t
t
t
f
SC
HD:STA
LOW
HIGH
SU;STA
HD;DAT
SU;DAT
SU;STO
BUF
2
C-bus specification.
t
LOW
t
SU;DAT
(2
DD
dependent
dependent
Software-
Software-
t
(n − 1)
SCL
2
TMP1941AF-250
Min
is switched off, the TMP1941AF does not comply with this requirement.
(n − 1)
t
r
Equation
0
+ 4) T
T
t
HIGH
Max
t
HD;DAT
fsys = 8 MHz, n = 4
4 (Note 1)
Standard Mode
400
300
200
100
Min
ns
250
4.0
4.7
4.0
4.7
4.0
4.7
0
6
0
0
10
Max
100
t
SU;STA
Sr
20
fsys
fsys = 32 MHz, n = 4
1 (Note 1)
TMP1941AF
Min
100
30
0.6
1.3
0.6
1.5
0.6
0.6
1.3
0
0
Fast Mode
t
SU;STO
40
P
MHz
Max
400
2003-03-27
t
BUF
Unit
kHz
µs
µs
µs
µs
µs
µs
µs
ns
µs
µs
2
C