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 65 of 172
The acknowledge mechanism using CLKACK pin is described in the following figure:
1
2
3
Fig 39. Clock acknowledge with CLKACK pin
Step1: PN544 request the clock from the system (for clock request, see previous
chapter: ‘Clock Request & Release’).
Step2: When the system clock is available, CLKACK pin goes high. PN544 is informed
that clock is available & stable.
Step3: When the system clock is no more available, CLKACK pin goes low.
9.4.4.3 Acknowledge through NXP_EVT_CLK_ACK event
In this mode,
PN544 will wait for an HCI event to consider that system clock is available.
To setup such a configuration, the following EEPROM area has to be set:
Table 57. Setting for clock acknowledge with HCI event
Name Length
(bytes)
Value(s) Comments
PlClockAck 1 2 PN544 will wait for an HCI
event
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