UM10204 Datasheet, PDF (46/64 Pages) NXP Semiconductors – I2C-bus specification and user manual

NXP Semiconductors
UM10204
I²C-bus specification and user manual
5.4 Ultra Fast-mode
Ultra Fast-mode (UFm) devices offer an increase in I²C-bus transfer speeds. UFm
devices can transfer information at bit rates of up to 5 Mbit/s. UFm devices offer push-pull
drivers, eliminating the pull-up resistors, allowing higher transfer rates. The same serial
bus protocol and data format is maintained as with the Sm, Fm, or Fm+ system. UFm bus
devices are not compatible with bidirectional I²C-bus devices.
6. Electrical specifications and timing for I/O stages and bus lines
6.1 Standard-, Fast-, and Fast-mode Plus devices
The I/O levels, I/O current, spike suppression, output slope control and pin capacitance
are given in Table 9. The I²C-bus timing characteristics, bus-line capacitance and noise
margin are given in Table 10. Figure 38 shows the timing definitions for the I²C-bus.
The minimum HIGH and LOW periods of the SCL clock specified in Table 10 determine
the maximum bit transfer rates of 100 kbit/s for Standard-mode devices, 400 kbit/s for
Fast-mode devices, and 1000 kbit/s for Fast-mode Plus. Devices must be able to follow
transfers at their own maximum bit rates, either by being able to transmit or receive at that
speed or by applying the clock synchronization procedure described in Section 3.1.7
which forces the master into a wait state and stretch the LOW period of the SCL signal.
In the latter case, the bit transfer rate is reduced.
UM10204
User manual
All information provided in this document is subject to legal disclaimers.
Rev. 4 — 13 February 2012
© NXP B.V. 2012. All rights reserved.
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