Rainbow-electronics MAX66140 Bedienungsanleitung PDF herunterladen (Seite 12)

MAX66140

Request Flags

The command descriptions on the subsequent pages begin with a byte called request flags. The ISO 15693 stan-

dard defines two formats for the request flags byte. The state of the Inventory_flag bit controls the function of the bits

in the upper half of the request flag byte. The function of the request flags is as follows:

Request Flags, Inventory_flag Bit Not Set

Bits 8 and 4: No Function

These bits have no function. They must be transmitted as 0.

Bit 7: Options Flag (Option_flag)

This bit is used with block read commands to include the block security status in the response. If not applicable for a

command, the Option_flag bit must be 0.

Bit 6: Address Flag (Address_flag)

This bit specifies whether all slaves in the master’s field that are in the selected or ready state process the request

(bit = 0) or only the single slave whose UID is specified in the request (bit = 1). If the Address_flag bit is 0, the

request must not include a UID. The combination of both the Select_flag and Address_flag bits being set (= 1) is not

valid.

Bit 5: Select Flag (Select_flag)

This bit specifies whether the request is processed only by the slave in the selected state (bit = 1) or by any slave

according to the setting of the Address_flag bit (bit = 0).

Bit 3: Inventory Flag (Inventory_flag)

This bit must be 1 for the Inventory command only. For all other commands, this bit must be 0.

Bit 2: Data Rate Flag (Data_rate_flag)

This bit specifies whether the response data packet is transmitted using the low data rate (bit = 0) or the high data

rate (bit = 1).

Bit 1: Subcarrier Flag (Subcarrier_flag)

This bit specifies whether the response data packet is transmitted using a single subcarrier (bit = 0) or two subcarri-

ers (bit = 1).

ISO 15693-Compliant Secure Memory

14 ______________________________________________________________________________________

ABRIDGED DATA SHEET

BIT 8 (MS) BIT 7 BIT 6 BIT 5 BIT 4 BIT 3 BIT 2 BIT1 (LS)

0 Option_flag Address_flag Select_flag 0 Inventory_flag (= 0) Data_rate_flag Subcarrier_flag

1 2 ... 7 8 9 10 11 12 13 14 15 16 17 ... 20 21

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Rainbow-electronics MAX66140 Bedienungsanleitung Seite 12