MCIMX255AJM4AR2 Freescale Semiconductor, MCIMX255AJM4AR2 Datasheet - Page 88

• Manufacturer Part Number: MCIMX255AJM4AR2
• Description: Processors - Application Specialized IMX25 1.2 AUTO
• Manufacturer: Freescale Semiconductor

Specifications of MCIMX255AJM4AR2

• Core: ARM926EJ-S
• Processor Series: MCIMX25
• Maximum Clock Frequency: 400 MHz
• Instruction / Data Cache Memory: 16 KB
• Data Ram Size: 128 KB
• Operating Supply Voltage: 1.15 V to 1.52 V
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• Package / Case: MAPBGA-400
• Interface Type: USB
• Memory Type: DDR2
• Minimum Operating Temperature: - 40 C

3.7.9.3
In RMII mode, FEC_TX_CLK is used as the REF_CLK, which is a 50 MHz ± 50 ppm continuous
reference clock. FEC_RX_DV is used as the CRS_DV in RMII. Other signals under RMII mode include
FEC_TX_EN, FEC_TXD[1:0], FEC_RXD[1:0] and FEC_RX_ER.
Figure 59
figure.
88
M16
M17
M18
M19
M20
M21
ID
FEC_TXD[1:0] (output)
FEC_TX_EN
FEC_RXD[1:0]
FEC_RX_ER
REF_CLK(FEC_TX_CLK) pulse width high
REF_CLK(FEC_TX_CLK) pulse width low
REF_CLK to FEC_TXD[1:0], FEC_TX_EN invalid
REF_CLK to FEC_TXD[1:0], FEC_TX_EN valid
FEC_RXD[1:0], CRS_DV(FEC_RX_DV), FEC_RX_ER to REF_CLK setup
REF_CLK to FEC_RXD[1:0], FEC_RX_DV, FEC_RX_ER hold
REF_CLK (input)
shows RMII mode timings.
CRS_DV (input)
RMII Mode Timing
i.MX25 Applications Processor for Automotive Products, Rev. 9
Figure 59. RMII Mode Signal Timing Diagram
Characteristic
Table 66
Table 66. RMII Signal Timing
M20
M18
describes the timing parameters (M16–M21) shown in the
M21
M19
M16
M17
Min.
35%
35%
—
3
2
2
Max.
65%
65%
12
—
—
—
Freescale Semiconductor
REF_CLK period
REF_CLK period
Unit
ns
ns
ns
ns