100BaseTX send
The 100BaseTX transmission function performs parallel-to-serial conversion, 4B/5B coding, scrambled code, NRZ to NRZI conversion,
MLT3 encoding and transmission. This circuit starts, in parallel with serial conversion, which will come from the MII of the data
The Mainland Affairs Council has become a 125MHz serial bit stream. The data and control stream are then converted to 4B/5B by scrambled encoding.
The serialized data is further converted from NRZ to NRZI format and then transmitted at MLT3 current output. output
The current is determined by the external 1% 3.01kΩ of the 1:1 transformer specific resistance. It has a typical rise/fall time and conforms to 4ns
Standards-related ANSI TP-PMD Amplitude Balance, Overshoot, and Timing Jitter. Wavy 10BaseT output
Also included in the 100BaseTX transmitter.
100BaseTX reception
Receive 100BaseTX adaptive equalization, DC recovery, MLT3 to NRZI conversion, data and clock performed by the receiving function
Recovery, NRZI to NRZ conversion, de-contest, 4B/5B decoding and serial to parallel conversion. The receiver starts
Filters and equalization of inter-symbol interference (ISI) compensation in twisted pair cables. Due to the amplitude
Loss and phase distortion are the right cable length functions, and the equalizer is adjusted to optimize its characteristics
Performance. In this design, the variable EQ makes a preliminary estimate based on the input signal comparison
For some known strength cable characteristics, then its tune itself is optimized. It's an ongoing process, and it can
Self-adjustment, such as changes in temperature to environmental changes.
The equalization signal then goes through the DC recovery and data conversion block. This DC recovery circuit is used for:
compensates for the effects of baseline drift and improves dynamic range. Differential data conversion circuit conversion
In MLT3 format back to NRZI. The slicing threshold is also adaptable.
The clock recovery circuit extracts the 125MHz clock from the edges of the NRZI signal. This recovered clock is then used to
The format is converted into NRZ signals of NRZI. Send a signal and then scramble by canceling the 4B/5B decoder.
Finally, the NRZ serial data is converted to MII format and the input data is provided by the MAC.
PLL clock synthesizers
The KS8997 generates system timing clocks of 125MHz, 62MHz, 25MHz and 10MHz. The internal clock generates one
External 25MHz crystal.
Scrambling/De-scrambling (100BaseTX only)
The purpose of this scrambling code is to propagate the power spectrum of the signal to reduce EMI and baseline drift. should
The data is shifted via a wide linear feedback shift of 11-bit registers (LFSRs). Using this can produce a 2047-bit non-speculation
Repeat sequence. The receiver competes for the data stream in the same order as the transmission.
10BaseT send
The output 10BaseT driver is incorporated into the 100BaseT driver to allow the use of the same magnetic transmission. They are
The domestic waveform and pre-output emphasize a typical 2.3V amplitude.
10BaseT reception
At the receiving end, input buffering and level detection squelch circuits are employed. Differential input circuit and a receiver
PLL performs decoding functions. The Manchester encoded data stream is divided into clock signals and NRZ data. One
Squelch circuits are less than 400mV reject or short pulse widths to level the signal and prevent noise in RXP or noise
RXM puts in a false trigger decoder. When the input exceeds the squelch limit, the PLL locks to the input signal
and KS8997 decoding data frames. The receiver clock remains active, and the idle time between data reception is obtained.
power management
Power saving mode
The KS8997 will turn off the energy detection circuit and PLL everything when the cable is not installed to the individual
Port Foundation. In other words, the KS8997 will shut down most of the internal circuitry to save power if there is no contact.
MDI/MDI-X automatic crossover
The KS8997 supports MDI/MDI-X auto-crossover. This is beneficial for either direct connection cables or the use of CAT-5
Crossover CAT-5 cable. The auto-sensing feature detects remote transmit and receive pairs, assigning the transmission correctly
and receive data from McRael equipment pairs. This can be very useful when the end user does not know the type of cable, and it is okay
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