by Leroy Davis
DataFlash uses a 7-Pin connector [1 rows of 7 pins]. The 7-pin connector is on 2.5-mil centers. The seven pin interface consists of three pins dedicated to the SPI serial bus [SCK, SI, and SO], a Chip Select signal [CS], a Chip Reset [RESET], a Write Protect line [WP], and an output Ready/Busy [RDY/Busy] signal. All of the control signals except the RDY signal are active low. The SPI interface uses the Serial Clock [SCK] line, Serial Input [SI], and the Serial Output [SO] line. How ever the physical DataFlash card does not have all the signals listed above, refer to the pinout table shown below. A few of the signals listed above may only be found on the DataFlash Integrated Circuits [ICs]. Refer to the Atmel Corporation website for available ICs which are compatible with the DataFlash interface. DataFlash is being produced in 2, 4, and 8Mbyte capacities
The DataFlash card dimensions are: 1.4mm thick x 24mm wide x 32mm long. The 7-pin cards are form factor compatible with the MultiMedia Card standard, and pinout compatible to the SPI version of the MMC card. A short description of the SPI interface is listed on the Integrated Circuit Buses
Pin # | Pin Name | Signal Function |
1 | CS* | Chip Select |
2 | SI | Serial Input [SPI] |
3 | GND | Ground |
4 | Vcc | Voltage Supply [2.7v or 3.6v] |
5 | SCK | Serial Clock [SPI] |
6 | NC | No Connect |
7 | SO | Serial Output [SPI] |
The graphic below provides a comparison of the different Removable memory Card standards. Many of the different Memory Card standards have descriptions listed on this web site. The different standards based on card size are provided. Refer to the Personal Computer Buses page for more information for different memory types, as listed here.
Refer to this page for a list of different Flash Memory Stick Formats.
MiniSD Card and SD Adaptor | MicroSD Card |
SD Memory Card | miniSD Card | microSD Card | |
Width | 24 mm | 20 mm | 11 mm |
Length | 32 mm | 21.5 mm | 15 mm |
Thickness | 2.1 mm | 1.4 mm | 1 mm |
Card Volume | 1,596 mm3 | 589 mm3 | 165 mm3 |
Weight | Approx. 2 g | Approx. 1 g | Approx. 0.5 g |
Operating Voltage | 2.7 - 3.6 V | 2.7 - 3.6 V | 2.7 - 3.6 V |
Write-protect Switch | YES | NO | NO |
Terminal Guards | YES | NO | NO |
Number of Pins | 9 pins | 11 pins | 8 pins |