PC8240 Просмотр технического описания (PDF) - Atmel Corporation

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PC8240

Integrated Processor Family

Atmel Corporation 

PC8240

Table 13. Two-wire Interface Input AC Timing Specifications (Continued)

Num Characteristics

Min

Max

Unit

Notes

6

Clock high period

5.0

(Time needed to either receive a data bit or

generate a START or STOP.)

–

CLKs

(1)(2)(5)

7

Data setup time

3.0

–

ns

(3)

8

Start condition setup time (for repeated start

4.0

condition only)

–

CLKs

(1)(2)

9

Stop condition setup time

4.0

–

CLKs

(1)(2)

Notes:

1. Units for these specifications are in SDRAM_CLK units.

2. The actual values depend on the setting of the Digital Filter Frequency Sampling Rate (DFFSR) bits in the Frequency

Divider Register I2CFDR. Therefore, the noted timings in the above table are all relative to qualified signals. The qualified

SCL and SDA are delayed signals from what is seen in real time on the two-wire interface bus. The qualified SCL, SDA

signals are delayed by the SDRAM_CLK clock times DFFSR times 2 plus 1 SDRAM_CLK clock. The resulting delay value is

added to the value in the table (where this note is referenced). See Figure 16 on page 27.

3. Timing is relative to the Sampling Clock (not SCL).

4. FDR[x] refers to the Frequency Divider Register I2CFDR bit x.

5. Input clock low and high periods in combination with the FDR value in the Frequency Divider Register (I2CFDR) determine

the maximum two-wire interface input frequency. See Figure 16 on page 27.

Table 14 provides the two-wire interface Frequency Divider Register (I2CFDR) informa-

tion for the PC8240.

At recommended operating conditions (see Table 3 on page 8) with GVdd = 3.3V ± 5%

and LVdd = 3.3V ± 5%

Table 14. PC8240 Maximum Two-wire Interface Input Frequency

Max Two-wire Interface Input Frequency(1)

FDR Hex(2)

Divider (Dec)(2)

SDRAM_CLK SDRAM_CLK SDRAM_CLK SDRAM_CLK

at 25 MHz

at 33 MHz

at 50 MHz

at 100 MHz

20, 21

160, 192

862

1.13 MHz

1.72 MHz

3.44 MHz

22, 23, 24, 25

224, 256, 320, 384

555

733

1.11 MHz

2.22 MHz

0, 1

288, 320

409

540

819

1.63 MHz

2, 3, 26, 27, 28, 29

384, 448, 480, 512, 640,

324

428

649

1.29 MHz

768

4, 5

576, 640

229

302

458

917

6, 7, 2A, 2B, 2C, 2D

768, 896, 960, 1024, 1280,

177

234

354

709

1536

8, 9

1152, 1280

121

160

243

487

A, B, 2E, 2F, 30, 31

1536, 1792, 1920, 2048,

92

2560, 3072

122

185

371

C, D

2304, 2560

62

83

125

251

E, F, 32, 33, 34, 35

3072, 3584, 3840, 4096,

47

62

95

190

5120, 6144

10, 11

4608, 5120

32

42

64

128

12, 13, 36, 37, 38, 39

6144, 7168, 7680, 8192,

24

31

48

96

10240, 12288

25

2149A–HIREL–05/02

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