Rainbow Electronics MAX66140 - Manual (Page 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