NXP Semiconductors PN544 C2 - Clock Request Using GPIO Pin

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 59 of 172
9.4.2.1 Clock Request using GPIO pin
The followi
ng figures show the 2 possible use of GPIO pin for Clock Request (GPIO2) &
acknowledge (GPIO1):
CLKREQ
System
Clock
1
CLKACK
(1)
Fig 32. Clock request with CLKREQ pin, acknowledge with CLCKACK pin
1
3
2
(1)
Fig 33. Clock request with CLKREQ pin, acknowledge with Timeout
Note: Step2 means that system clock is stable and available for PN544.