10-8
MPC8240 Integrated Processor User’s Manual
I
2
C Register Descriptions
Table 10-3 describes the bit settings of I2CADR.
10.3.2 I
2
C Frequency Divider Register (I2CFDR)
The I2CFDR, shown in Figure 10-4, configures the sampling rate and the clock bit rate for
the I
2
C unit.
Figure 10-4. I
2
C Frequency Divider Register (I2CFDR)
Table 10-4 describes the bit settings of the I2CFDR.
Table 10-3. I2CADR Field Descriptions—Offset 0x0_3000
Bits
Name
Reset
Value
R/W
Description
31–8
—
All zeros
R
Reserved
7–1
ADDR
0x00
R/W
Slave address. Contains the specific address to which the MPC8240
responds as a slave on the I
2
C interface. Note that the default mode of the
I
2
C interface is slave mode for an address match.
0
—
0
R
Reserved
Table 10-4. I2CFDR Field Descriptions—Offset 0x0_3004
Bits
Name
Reset
Value
R/W
Description
31–14
—
All 0s
R
Reserved
13–8
DFFSR
0x10
R/W
Digital filter frequency sampling rate—To assist in filtering out signal noise, the
sample rate is programmable; this field is used to prescale the frequency at
which the digital filter takes samples from the I
2
C bus. The resulting sampling
rate is the local memory frequency (SDRAM_CLK) divided by the non-zero
value set in this field. If DFFSR is set to zero, the I
2
C bus sample points default
to the reset divisor 0x10.
7–6
—
00
R
Reserved
5–0
FDR
0x00
R/W
Frequency divider ratio—Used to prescale the clock for bit rate selection. The
serial bit clock frequency of SCL is equal to the local memory clock
(SDRAM_CLK) divided by the divider shown in Table 10-5. Note that the
frequency divider value can be changed at any point in a program.
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
DFFSR
0 0
FDR
31
14 13
8
7
6
5
0
Reserved
Содержание MPC8240
Страница 1: ...MPC8240UM D Rev 1 1 2001 MPC8240 Integrated Processor User s Manual ...
Страница 38: ...xviii MPC8240 Integrated Processor User s Manual TABLES Table Number Title Page Number ...
Страница 48: ...xlviii MPC8240 Integrated Processor User s Manual Acronyms and Abbreviations ...
Страница 312: ...6 94 MPC8240 Integrated Processor User s Manual ROM Flash Interface Operation ...
Страница 348: ...7 36 MPC8240 Integrated Processor User s Manual PCI Host and Agent Modes ...
Страница 372: ...8 24 MPC8240 Integrated Processor User s Manual DMA Register Descriptions ...
Страница 394: ...9 22 MPC8240 Integrated Processor User s Manual I2O Interface ...
Страница 412: ...10 18 MPC8240 Integrated Processor User s Manual Programming Guidelines ...
Страница 454: ...12 14 MPC8240 Integrated Processor User s Manual Internal Arbitration ...
Страница 466: ...13 12 MPC8240 Integrated Processor User s Manual Exception Latencies ...
Страница 516: ...16 14 Watchpoint Trigger Applications ...
Страница 538: ...B 16 MPC8240 Integrated Processor User s Manual Setting the Endian Mode of Operation ...
Страница 546: ...C 8 MPC8240 Integrated Processor User s Manual ...
Страница 640: ...INDEX Index 16 MPC8240 Integrated Processor User s Manual ...