Datasheet

LPC84x All information provided in this document is subject to legal disclaimers. © NXP Semiconductors N.V. 2018. All rights reserved.
Product data sheet Rev. 1.7 — 27 February 2018 63 of 97
NXP Semiconductors
LPC84x
32-bit Arm Cortex-M0+ microcontroller
[8] The maximum t
HD;DAT
could be 3.45 s and 0.9 s for Standard-mode and Fast-mode but must be less than
the maximum of t
VD;DAT
or t
VD;ACK
by a transition time (see UM10204). This maximum must only be met if
the device does not stretch the LOW period (t
LOW
) of the SCL signal. If the clock stretches the SCL, the
data must be valid by the set-up time before it releases the clock.
[9] t
SU;DAT
is the data set-up time that is measured with respect to the rising edge of SCL; applies to data in
transmission and the acknowledge.
[10] A Fast-mode I
2
C-bus device can be used in a Standard-mode I
2
C-bus system but the requirement
t
SU;DAT
= 250 ns must then be met. This will automatically be the case if the device does not stretch the
LOW period of the SCL signal. If such a device does stretch the LOW period of the SCL signal, it must
output the next data bit to the SDA line t
r(max)
+ t
SU;DAT
= 1000 + 250 = 1250 ns (according to the
Standard-mode I
2
C-bus specification) before the SCL line is released. Also the acknowledge timing must
meet this set-up time.
Fig 29. I
2
C-bus pins clock timing
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