MPC8572E PowerQUICC III Integrated Processor Hardware Specifications, Rev. 5
68
Freescale Semiconductor
I
2C
13.2
I2C AC Electrical Specifications
Table 55 provides the AC timing parameters for the I2C interfaces. Table 55. I2C AC Electrical Specifications
At recommended operating conditions with OVDD of 3.3 V ± 5%. All values refer to VIH (min) and VIL (max) levels (see Table 2). Parameter
Symbol1
Min
Max
Unit
SCL clock frequency
fI2C
0400
kHz4
Low period of the SCL clock
tI2CL
1.3
—
μs
High period of the SCL clock
tI2CH
0.6
—
μs
Setup time for a repeated START condition
tI2SVKH
0.6
—
μs
Hold time (repeated) START condition (after this period, the first
clock pulse is generated)
tI2SXKL
0.6
—
μs
Data setup time
tI2DVKH
100
—
ns
Data input hold time:
CBUS compatible masters
I2C bus devices
tI2DXKL
—
02
—
μs
Data output delay time
tI2OVKL
—0.93
μs
Setup time for STOP condition
tI2PVKH
0.6
—
μs
Bus free time between a STOP and START condition
tI2KHDX
1.3
—
μs
(including hysteresis)
VNL
0.1
× OVDD
—V
Noise margin at the HIGH level for each connected device
(including hysteresis)
VNH
0.2
× OVDD
—V
Capacitive load for each bus line
Cb
—
400
pF
Notes:
1.The symbols used for timing specifications herein follow the pattern t(first two letters of functional block)(signal)(state)(reference)(state) for
inputs and t(first two letters of functional block)(reference)(state)(signal)(state) for outputs. For example, tI2DVKH symbolizes I
2C timing (I2)
with respect to the time data input signals (D) reach the valid state (V) relative to the tI2C clock reference (K) going to the high
(H) state or setup time. Also, tI2SXKL symbolizes I
2C timing (I2) for the time that the data with respect to the START condition
(S) went invalid (X) relative to the tI2C clock reference (K) going to the low (L) state or hold time. Also, tI2PVKH symbolizes I
2C
timing (I2) for the time that the data with respect to the STOP condition (P) reaching the valid state (V) relative to the tI2C clock
reference (K) going to the high (H) state or setup time.
2. As a transmitter, the MPC8572E provides a delay time of at least 300 ns for the SDA signal (referred to the VIHmin of the
SCL signal) to bridge the undefined region of the falling edge of SCL to avoid unintended generation of START or STOP
condition. When the MPC8572E acts as the I2C bus master while transmitting, the MPC8572E drives both SCL and SDA.
As long as the load on SCL and SDA are balanced, the MPC8572E would not cause unintended generation of START or
STOP condition. Therefore, the 300 ns SDA output delay time is not a concern. If, under some rare condition, the 300 ns SDA
output delay time is required for the MPC8572E as transmitter, application note AN2919 referred to in note 4 below is
recommended.
3.The maximum tI2OVKL has only to be met if the device does not stretch the LOW period (tI2CL) of the SCL signal.
4. The requirements for I2C frequency calculation must be followed. Refer to Freescale application note AN2919,
Determining
the I2C Frequency Divider Ratio for SCL.