21

ATA5577C [DATASHEET]

9187H–RFID–07/14

Figure 5-13. Long-leading-reference Protocol

5.12.5 Leading-zero-reference Protocol

If the device is programmed in this mode, it will always expect a reference pulse before the command data itself. This pulse

length should correspond exactly to the length of the zero bits in the following command. All further lengths of the zero and

one bits of the command are derived from the reference pulse. Therefore, downlink performance is optimal in different

environmental conditions.

Figure 5-14. Leading-zero-reference Protocol

Table 5-11. Downlink Data Coding Scheme with Long Leading Reference

Parameter

Remark

Symbol

Normal Downlink

Fast Downlink

Unit

Min.

Typ.

Max.

Min.

Typ.

Max.

Start gap

8

15

50

8

15

50

Write gap

8

10

20

8

10

20

Write data

coding (gap

separation)

Reference Pulse

152

160

168

140

144

148

136 clocks + 0 data bit

132 clocks + 0 data bit

0 data

1 data

Note:

1

Reference pulse

0

a)

10

b)

1

Reference pulse

0

c)

Table 5-12. Downlink Data Coding Scheme with Leading-zero Reference

Parameter

Remark

Symbol

Normal Downlink

Fast Downlink

Unit

Min.

Typ.

Max.

Min.

Typ.

Max.

Start gap

8

15

50

8

15

50

Write gap

8

10

20

8

10

20

Write data

coding (gap

separation)

Reference Pulse

12

–

72

8

–

68

0 data

1 data

Note:

10

(0)

Reference pulse