Eccel Technology Ltd BIORADRDR0200 Manuel D’Utilisation

4.2.24 Halt (0x18)

The Halt command takes no arguments. It halts the tag and turns off the RF field. It must be executed at the end of
each operation on a tag to disable the antenna and reduce the power consumption.

4.2.25 Calculate CRC (0x19)

Table 4.25

The Calculate CRC command takes as arguments the Memory Address, the Data Length in bytes and the Data Buffer
Offset. The CRC calculation starts at the byte pointed at by the memory address and is done on the ‘Data Length’
number of bytes in the volatile memory. The result is stored in the Data Buffer at the Data Buffer Offset index. The
result is a 16-bit unsigned value with least significant byte first. The CRC calculation code is shown below.

static const uint16_t CCITTCRCTable [256] = {
0x0000, 0x1021, 0x2042, 0x3063, 0x4084, 0x50a5,
0x60c6, 0x70e7, 0x8108, 0x9129, 0xa14a, 0xb16b,
0xc18c, 0xd1ad, 0xe1ce, 0xf1ef, 0x1231, 0x0210,
0x3273, 0x2252, 0x52b5, 0x4294, 0x72f7, 0x62d6,
0x9339, 0x8318, 0xb37b, 0xa35a, 0xd3bd, 0xc39c,
0xf3ff, 0xe3de, 0x2462, 0x3443, 0x0420, 0x1401,
0x64e6, 0x74c7, 0x44a4, 0x5485, 0xa56a, 0xb54b,
0x8528, 0x9509, 0xe5ee, 0xf5cf, 0xc5ac, 0xd58d,
0x3653, 0x2672, 0x1611, 0x0630, 0x76d7, 0x66f6,
0x5695, 0x46b4, 0xb75b, 0xa77a, 0x9719, 0x8738,
0xf7df, 0xe7fe, 0xd79d, 0xc7bc, 0x48c4, 0x58e5,

Command Number

Command Name

Valid Tag Types

Argument Offset [bytes]

0x00

0x02

0x04

Argument Name

Memory Address

Data Length

Data Buffer Offset

Argument Size [bytes]

0x02

0x01

Argument Description

Byte address in the

memory from which

the CRC calculation is

to start. This is an

unsigned 16-bit value

with least significant

byte first.

Data length in bytes

upon which the CRC is
to be performed. This

is an unsigned 16-bit

value with least

significant byte first.

Buffer offset in bytes

where the CRC value is

to be stored. The CRC

value is 16-bit

unsigned with least

significant byte first.

0x19

Calculate CRC