Q1) answer the following question regarding these two devices MicroSD card break
ID: 3889018 • Letter: Q
Question
Q1) answer the following question regarding these two devices
MicroSD card breakout board+ by Adafruit https://www.adafruit.com/products/254
SparkFun Level Shifting microSD Breakout https://www.sparkfun.com/products/13743
a) Locate and analyze the schematics for the two breakout boards. You can find them starting at the links above. What appears to be the major difference between the two designs? (note: you have to be more specific than a different level-shifter chip was used, and I do not care about the voltage regulator or decoupling caps – focus on the SPI lines)
b) Focusing on the DO (Data Out) signal of the SD card, what are the implications of each design as far as the ATmega644P is concerned? (hint: take a look at the ATmega644 datasheet as well as the datasheet of a typical SD card and perhaps the datasheets for 74HC4050 and TXB0104, all in the shared Box folder, and compare logic voltage levels – VOH, VOL, VIH, VIL)
Explanation / Answer
a)
The SparkFun Level Shifting microSD Breakout is very like the SparkFun microSD Transflash Breakout, however, with the included level moving equipment, this board enables you to use a microSD card at Arduino's SD library's best speed on a 5V system.microSD card attachment to help ventures which require putting away a lot of information from Grove sensor.
Not only a straightforward breakout board, this microSD connector runs the additional mile with worked in 3.3V voltage controller and rationale level transformation from 5V to 3.3V. So you can utilize this board with 5V and 3.3V frameworks
B)
Correspondence with an SD card should be possible in one of two modes: the SD mode or the SPI mode. As a matter of course, the SD card works in the SD mode. In any case, we'll work with the SPI mode and speak with it utilizing the SPI convention. Correspondence with the SD card is performed by sending summons to it and accepting reactions from it. A substantial SD card order comprises of 48 bits. The furthest left two bits are the begin bits which we set to (01). They are trailed by a 6-bit order number and a 32-bit contention where extra data might be given. Next, there are 7 bits containing a Cyclic Redundancy Check (CRC) code.
The CRC code is utilized by the SD card to check the respectability of a charge it gets. As a matter of course, the SD card overlooks the CRC bits for most orders (with the exception of CMD8) unless a client asks for that CRC bits be checked after getting each message. Sending a summon to the SD card is performed in a serial mold. As a matter of course, the MOSI line is set to 1 to demonstrate that no message is being sent.
The way toward communicating something specific starts with setting its most significant bit on the MOSI line and after that flipping the SD CLK motion from 0 to 1 and after that once more from 1 to 0. At that point, the second piece is put on the MOSI line and again the SD CLK flag is flipped twice. Rehashing this method for each piece permits the SD card to get a total summons. Once the SD card gets a summon it will start preparing it. To react to a summon, the SD card requires the SD CLK flag to flip for no less than 8 cycles. Your program should flip the SD CLK flag and keep up the MOSI line high while sitting tight for a reaction. The length of a reaction message changes relying upon the summon. The majority of the summons get a reaction for the most part as 8-bit messages, with two special cases where the reaction comprises of 40 bits. To guarantee the best possible operation of the SD card, the SD CLK flag ought to have a recurrence in the scope of 100 to 400 kHz.
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.