NXP Semiconductors
UM191812
PN544 C2 User Manual
191812 All information provided in this document is subject to legal disclaimers. © NXP B.V. 2010. All rights reserved.
User Manual Rev. 1.2 — 2010-06-16 61 of 172
9.4.3.1 No clock request
In the case of a clock al
ways provided by the system, the request/acknowledge
mechanism is not needed. To setup such a configuration, the following EEPROM area
has to be set (See ’
HW configuration’ chapter):
Table 52. Setting for no clock request
Name Length
(bytes)
Value(s) Comments
PlClockRequest 1 0 System clock always
available
Note: No others settings are required for this configuration. It means that the following
setup is not needed and not taken into account by PN544.
9.4.3.2 Request through CLKREQ pin
In this mode,
PN544 will request the clock by setting the CLKREQ pin (GPIO2) to high.
To setup such a configuration, the following EEPROM area has to be set:
Table 53. Setting for clock request with CLKREQ pin
Name Length
(bytes)
Value(s) Comments
PlClockRequest 1 0x01 PN544 will request clock
from system by using the
CLKREQ pin
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