MCIMX251AJM4 Freescale Semiconductor, MCIMX251AJM4 Datasheet - Page 89

• Manufacturer Part Number: MCIMX251AJM4
• Description: IC MPU IMX25 AUTO 400MAPBGA
• Manufacturer: Freescale Semiconductor
• Series: i.MX25r

Specifications of MCIMX251AJM4

• Core Processor: ARM9
• Core Size: 32-Bit
• Speed: 400MHz
• Connectivity: 1-Wire, CAN, EBI/EMI, Ethernet, I²C, MMC, SmartCard, SPI, SSI, UART/USART, USB OTG
• Peripherals: DMA, I²S, POR, PWM, WDT
• Number Of I /o: 128
• Program Memory Type: External Program Memory
• Ram Size: 144K x 8
• Voltage - Supply (vcc/vdd): 1.15 V ~ 1.52 V
• Data Converters: A/D 3x12b
• Oscillator Type: External
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 400-MAPBGA
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -
• Program Memory Size: -

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.
Freescale Semiconductor
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. 8
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
35%
35%
Min.
—
3
2
2
Max.
65%
65%
12
—
—
—
REF_CLK period
REF_CLK period
Unit
ns
ns
ns
ns
89