HFA3860 Datasheet, PDF (4/40 Pages) Intersil Corporation – 11 Mbps Direct Sequence Spread Spectrum Baseband Processor

HFA3860
Pin Descriptions (Continued)
NAME
TX_PE
TXD
TXCLK
TX_RDY
CCA
RXD
RXCLK
MD_RDY
RX_PE
SD
SCLK
SDI
R/W
CS
TEST 7:0
PIN
2
3
4
5
32
35
36
34
33
25
24
23
8
9
37, 38, 39,
40, 43, 44,
45, 46
TYPE I/O
DESCRIPTION
I
When active, the transmitter is configured to be operational, otherwise the transmitter is in standby
mode. TX_PE is an input from the external Media Access Controller (MAC) or network processor to
the HFA3860. The rising edge of TX_PE will start the internal transmit state machine and the falling
edge will initiate shut down of the state machine. TX_PE envelopes the transmit data except for the last
bit. The transmitter will continue to run for 3 symbols after TX_PE goes inactive to allow the PA to shut
down gracefully.
I
TXD is an input, used to transfer MAC Payload Data Unit (MPDU) data from the MAC or network
processor to the HFA3860. The data is received serially with the LSB first. The data is clocked in the
HFA3860 at the rising edge of TXCLK.
O
TXCLK is a clock output used to receive the data on the TXD from the MAC or network processor to
the HFA3860, synchronously. Transmit data on the TXD bus is clocked into the HFA3860 on the rising
edge. The clocking edge is also programmable to be on either phase of the clock. The rate of the clock
will be dependent upon the data rate that is programmed in the signalling field of the header.
O
TX_RDY is an output to the external network processor indicating that Preamble and Header
information has been generated and that the HFA3860 is ready to receive the data packet from the
network processor over the TXD serial bus. The TX_RDY returns to the inactive state when the last
chip of the last symbol has been output.
O
Clear Channel Assessment (CCA) is an output used to signal that the channel is clear to transmit. The
CCA algorithm makes its decision as a function of RSSI, Energy Detect (ED), and Carrier Sense
(CRS). The CCA algorithm and its features are described elsewhere in the data sheet.
Logic 0 = Channel is clear to transmit.
Logic 1 = Channel is NOT clear to transmit (busy).
This polarity is programmable and can be inverted.
O
RXD is an output to the external network processor transferring demodulated Header information and
data in a serial format. The data is sent serially with the LSB first. The data is frame aligned with
MD_RDY.
O
RXCLK is the bit clock output. This clock is used to transfer Header information and payload data
through the RXD serial bus to the network processor. This clock reflects the bit rate in use. RXCLK is
held to a logic “0” state during the CRC16 reception. RXCLK becomes active after the SFD has been
detected. Data should be sampled on the rising edge. This polarity is programmable and can be
inverted.
O
MD_RDY is an output signal to the network processor, indicating header data and a data packet are
ready to be transferred to the processor. MD_RDY is an active high signal and it envelopes the data
transfer over the RXD serial bus. MD_RDY goes active when the SFD is detected and returns to its
inactive state when RX_PE goes inactive or an error is detected in the header.
I
When active, the receiver is configured to be operational, otherwise the receiver is in standby mode.
This is an active high input signal. In standby, RX_PE inactive, all A/D converters are disabled.
I/O
SD is a serial bi-directional data bus which is used to transfer address and data to/from the internal
registers. The bit ordering of an 8-bit word is MSB first. The first 8 bits during transfers indicate the
register address immediately followed by 8 more bits representing the data that needs to be written or
read at that register.
I
SCLK is the clock for the SD serial bus.The data on SD is clocked at the rising edge. SCLK is an input
clock and it is asynchronous to the internal master clock (MCLK)The maximum rate of this clock is
11MHz or one half the master clock frequency, whichever is lower.
I
This pin is not used in the 4 wire interface described in this data sheet. It should not be left floating.
I
R/W is an input to the HFA3860 used to change the direction of the SD bus when reading or writing
data on the SD bus. R/W also enables the serial shift register used in a read cycle. R/W must be set
up prior to the rising edge of SCLK. A high level indicates read while a low level is a write.
I
CS is a Chip select for the device to activate the serial control port.The CS doesn’t impact any of the
other interface ports and signals, i.e., the TX or RX ports and interface signals. This is an active low
signal. When inactive SD, SCLK, and R/W become “don’t care” signals.
O
This is a data port that can be programmed to bring out internal signals or data for monitoring. These
bits are primarily reserved by the manufacturer for testing. A further description of the test port is given
at the appropriate section of this data sheet.
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