Instruction manual

Appendix B. PC/CF Card Information

PC or CompactFlash (CF) cards provide a relatively inexpensive, off-the-shelf

means of retrieving data from many of our CRBasic dataloggers or expanding the

on-board datalogger memory. The datalogger’s memory can be expanded up to 2

Gbytes with the use of these cards. Some dataloggers can use either a PC or CF

card, and others can only use a CF card with the appropriate expansion module.

Table B-1 lists the compatibility between dataloggers and cards.

Table B-1. CRBasic Dataloggers and PC/CF Cards

Datalogger Card Slot CF Card PC Card

CR200 Not Available Not Available Not Available

CR800/850 Not Available Not Available Not Available

CR1000 CFM100 or NL115 Yes No

CR3000 CFM100 or NL115 Yes No

CR5000 Built In Yes, with Adaptor Yes

CR9000(X) Built In Yes, with Adaptor Yes

PC/CF cards use NAND (Not AND) Flash (non-volatile) memory which has the

following characteristics: high density, low cost/bit, sequential access, scalable,

and a single standard. There are two types of NAND Flash memory: Single-

Level Cell (SLC) and Multi-Level Cell (MLC). SLC NAND Flash sometimes

called Binary Flash, store one bit of data per memory cell and has two states:

erased (1) or programmed (0). MLC NAND Flash store two bits of data per

memory cell and has four states: erased (11), two thirds (10), one third (01), or

programmed (00)

. At first glance, the MLC cards seem more desirable, because

each cell can hold more information. However, as summarized in Table B-2, the

increased data storage comes at a price, mainly speed.

Table B-2. SLC and MLC Performance Characteristics

SLC MLC

Voltage 3.3 V / 1.8 V 3.3 V

Page Size / Block Size 2KB / 128KB 512 B / 32 KB or 2 KB /

256 KB

Access Time (maximum) 25 µs 70 µs

Page Program Time 250 µs 1.2 ms

Partial Programming Yes No

Endurance 100,000 10,000

Write Data Rate 8 MB/s+ 1.5 MB/s

There is a notable performance difference between the two types of NAND Flash

memory. In a performance study by Samsung Electronics

, Samsung found that

SLC outperformed MLC, offering greater durability, running 300% faster in write

mode, and 43% faster in read mode. While MLC Flash increases the overall

density of data storage, which therefore decreases cost; it does so at the expense of

data reliability, performance and memory management. Furthermore, MLC

technology is more prone to failure, data corruption, or incorrect reading due to

memory cell degradation from the additional energy required during operations

B-1