![]() |
Electronic Components Datasheet Search |
|
AD7278BRMZ Datasheet(PDF) 24 Page - Analog Devices |
|
AD7278BRMZ Datasheet(HTML) 24 Page - Analog Devices |
24 / 28 page ![]() AD7276/AD7277/AD7278 Data Sheet Rev. D | Page 24 of 28 AD7278 IN A 10 SCLK CYCLE SERIAL INTERFACE For the AD7278, if CS is brought high during the 10 th rising edge after the two leading zeros and eight bits of the conversion are provided, then the part can achieve a 4 MSPS throughput rate. For the AD7278, the track-and-hold goes back into track mode on the ninth rising edge. In this case, a fSCLK = 48 MHz and throughput of 4 MSPS result in a cycle time of t2 + 8.5(1/fSCLK) + tACQ = 250 ns, where t2 = 6 ns minimum and tACQ = 67 ns. This satisfies the requirement of 60 ns for tACQ. Figure 35 shows that tACQ comprises 0.5(1/fSCLK) + t8 + tQUIET, where t8 = 14 ns max. This allows a value of 43 ns for tQUIET, satisfying the minimum requirement of 4 ns. MICROPROCESSOR INTERFACING AD7276/AD7277/AD7278 to Blackfin Processor The Analog Devices, Inc., family of Blackfin DSPs, including the ADSP-BF531, ADSP-BF532, ADSP-BF533, ADSP-BF534, ADSP-BF535, ADSP-BF536, ADSP-BF537, ADSP-BF538, ADSP-BF538F, ADSP-BF539, and ADSP-BF539F, interfaces directly to the AD7276/AD7277/AD7278 without requiring glue logic. (These DSPs are represented by the ADSP-BF531 in Figure 36.) Set up the SPORT0 Receive Configuration 1 Register up as outlined in Table 9. AD7276/ AD7277/ AD7278* ADSP-BF531* SCLK RSCLK0 SPORT0 DR0PRI RFS0 DT0PRI DOUT CS DIN *ADDITIONAL PINS OMITTED FOR CLARITY Figure 36. Interfacing with the ADSP-BF531 Table 9. The SPORT0 Receive Configuration 1 Register (SPORT0_RCR1) Setting Description RCKFE = 1 Sample data with falling edge of RSCLK LRFS = 1 Active low frame signal RFSR = 1 Frame every word IRFS = 1 Internal RFS used RLSBIT = 0 Receive MSB first RDTYPE = 00 Zero fill IRCLK = 1 Internal receive clock RSPEN = 1 Receive enabled SLEN = 1111 16-bit data-word (or can be set to 1101 for 14-bit data-word) TFSR = RFSR = 1 To implement the power-down modes, SLEN should be set to 1001 to issue an 8-bit SCLK burst. |
|