dspb56011 Freescale Semiconductor, Inc, dspb56011 Datasheet - Page 52

• Manufacturer Part Number: dspb56011
• Description: 24-bit Dvd Digital Signal Processor
• Manufacturer: Freescale Semiconductor, Inc

Specifications
Serial Host Interface (SHI) I2C Protocol Timing
Considerations for Programming the SHI Clock Control Register
(HCKR)—Clock Divide Ratio
2-26
C
C
R
R
Bus Load
L
L
P
P
= 50 pF,
= 50 pF,
= 2 k
= 2 k
Table 2-12 Considerations for Programming the SHI Clock control Register (HCKR)
The master must generate a bus free time greater than T172 slave when operating
with a DSP56011 SHI I
Example: for C
when operating with a DSP56011 SHI I
must generate a bus free time greater than 36 ns (T172 slave). Thus, the minimum
permissible T
master). This implies a maximum I
In general, bus performance may be calculated from the C
the input filter modes and operating frequencies of the master and the slave.
Table 2-13 on page 2-27 contains the expressions required to calculate all relevant
performance timing for a given C
Note: T177 (t
81 MHz
95 MHz
Master
Oper-
ating
Freq.
Conditions to be Considered
computed using the value of C
of the other timing values in Table 2-13 on page 2-27.
I
81 MHz
95 MHz
DSP56011 Technical Data Sheet, Rev. 1
2
r
CCP
Oper-
Slave
) is computed using the values of C
ating
Freq.
L
= 50 pF, R
is 52 T
2
Preliminary Information
C slave. Table 2-12 describes a few examples.
Bypassed
Bypassed
Narrow
Narrow
Master
Mode
Filter
Wide
Wide
P
C
= 2 k , f = 81 MHz, Bypassed filter mode: The master,
, which gives a bus free time of at least 41 ns (T172
L
Bypassed
Bypassed
2
and R
Narrow
Narrow
C serial frequency of 1010 kHz.
Mode
Slave
Filter
Wide
Wide
L
2
. The two values are used in computing many
C slave with an 81 MHz operating frequency,
P
.
Slave
T172
36 ns
60 ns
95 ns
32 ns
56 ns
91 ns
L
and R
56
62
64
71
52
60
issible
Perm-
t
Min.
I
2
CCP
Resulting Limitations
T
T
T
T
T
T
P
L
C
C
C
C
C
C
and T178 (T
and R
Master
92.8 ns
103 ns
T172
41 ns
66 ns
35 ns
56 ns
P
of the bus,
MOTOROLA
F
) is
Maximum
Frequency
I
1010 kHz
1030 kHz
2
825 kHz
634 kHz
843 kHz
645 kHz
C Serial