Z87200 Datasheet, PDF (27/54 Pages) Zilog, Inc. – Spread-Spectrum Transceiver

Zilog
Z87200
Spread-Spectrum Transceiver
All signals available at this port, with one exception, are ex- accessing the transmitter test points is completely different
pressed as two’s complement values, ranging from –128 than the method by which the receiver test points are ac-
to +127 (80_H to 7F_H). The PN Matched Filter power output
values, available when the value in bits 3-0 of address 38_H
cessed. The state of the other address lines does not af-
fect this function, and this function is always enabled. The
4
is set to either 1_H or 8_H, is an unsigned binary number, availability of TXTEST output signals is only supported for
ranging from 0 to 255 (0_H to FF_H).
TXIFCLK speeds less than 20 MHz; output with clock
speeds greater than 20 MHz will be indeterminate.
The reset sequence that occurs when the receiver is dis-
abled will also reset the contents of address 38_H to a value
of 0. If the RXTEST_7-0 bus is to be used to observe any
function other than the PN Matched Filter I and Q inputs,
Table 5. Transmitter Test Functions
ADDR_1-0
TXTEST
Description
then the appropriate value must be rewritten.
0_H
ISM
Unspread I Symbol
TXTEST (Pin 59)
1_H
QSYM
Unspread Q Symbol
Transmitter Test Output. TXTEST provides access to 3
2_H
test points within the transmitter as shown in The pin out-
SCODE
Spreading Code
put is selected according to the state of the two least sig-
nificant bits of the address line, ADDR_1-0 and the assign-
ments shown in Table 5. Note that this method of
Figure 10. Transmitter and Receiver Test Points
DS96WRL0400
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