Specifications
Serial Host Interface (SHI) I
2
C Protocol Timing
MOTOROLA
DSP56367
3-63
3.13.1
PROGRAMMING THE SERIAL CLOCK
The programmed serial clock cycle, T
I
2
CCP
, is specified by the value of the HDM[7:0] and
HRS bits of the HCKR (SHI clock control register).
The expression for T
I
2
CCP
is
T
I
2
CCP
= [T
C
×
2
×
(HDM[7:0] + 1)
×
(7
×
(1 – HRS) + 1)]
where
–
HRS is the prescaler rate select bit. When HRS is cleared, the fixed
divide-by-eight prescaler is operational. When HRS is set, the prescaler is
bypassed.
–
HDM[7:0] are the divider modulus select bits. A divide ratio from 1 to 256
(HDM[7:0] = $00 to $FF) may be selected.
In I
2
C mode, the user may select a value for the programmed serial clock cycle from
187
Last SCL edge to HREQ output not
deasserted
T
AS;RQO
ns
Filters bypassed
2
×
T
C
+ 30
46.7
—
46.7
—
Narrow filters enabled
2
×
T
C
+ 80
96.7
—
96.7
—
Wide filters enabled
2
×
T
C
+ 135
151.6
—
151.6
—
188
HREQ in assertion to first SCL edge
T
AS;RQI
0.5
×
T
I
2
CCP
-
0.5
×
T
C
- 21
ns
Filters bypassed
4440
—
1041
—
Narrow filters enabled
4373
—
999
—
Wide filters enabled
4373
—
958
—
189
First SCL edge to HREQ in not asserted
(HREQ in hold time)
t
HO;RQI
0.0
—
0.0
—
ns
Note:
1.
V
CC
= 1.8 V
±
5%; T
J
=
0°C to +95°C
2.
Pull-up resistor: R
P
(min) = 1.5 kOhm
3.
Capacitive load: C
b
(max) = 400 pF
4.
It is recommended to enable the wide filters when operating in the I
2
C Standard Mode.
5.
It is recommended to enable the narrow filters when operating in the I
2
C Fast Mode.
Table 3-20 SHI I
2
C Protocol Timing (Continued)
No.
Characteristics
1,2,3
Symbol/
Expression
Standard Mode
4
Fast Mode
5
Unit
Min
Max
Min
Max
Summary of Contents for DSP56367
Page 16: ...xvi MOTOROLA CONTENTS Paragraph Number Title Page Number ...
Page 22: ...xxii MOTOROLA List of Figures Figure Number Title Page Number ...
Page 26: ...xxvi MOTOROLA List of Tables Table Number Title Page Number ...
Page 148: ...4 6 DSP56367 MOTOROLA Design Considerations PLL Performance Issues ...
Page 248: ...9 30 DSP56367 MOTOROLA Serial Host Interface SHI Programming Considerations ...
Page 306: ...10 58 DSP56367 MOTOROLA Enhanced Serial Audio Interface ESAI ESAI Initialization Examples ...
Page 389: ...Bootstrap ROM Contents MOTOROLA DSP56367 A 15 end ...
Page 390: ...A 16 DSP56367 MOTOROLA Bootstrap ROM Contents ...
Page 432: ...C 8 DSP56367 MOTOROLA JTAG BSDL ...
Page 484: ...D 52 DSP56367 MOTOROLA Programmer s Reference ...
Page 490: ...E 6 DSP56367 MOTOROLA Power Consumption Benchmark ...
Page 516: ...F 26 DSP56367 MOTOROLA IBIS Model ...
Page 522: ...Index 6 MOTOROLA Index ...
Page 523: ......