XE8000EV108 Semtech, XE8000EV108 Datasheet - Page 101

• Manufacturer Part Number: XE8000EV108
• Description: EVAL BOARD FOR XE8806/XE8807
• Manufacturer: Semtech
• Type: MCUr

Specifications of XE8000EV108

• Contents: Fully Assembled Evaluation Board
• For Use With/related Products: XE88LC06AMI026
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

This documentation shows how to set-up the data transmission between the microcontroller and the XE1202A. For
detailed information on the XE1202A functionality, external components, serial interface protocol and register set-
up, please refer to the XE1202A datasheet.
14.12.2.2 Microcontroller clock source derived from XE1202A crystal oscillator
The XE1202A has a programmable output clock derived from the 39MHz crystal oscillator. This clock can be
routed to the external clock input of the microcontroller (see Figure 14-9 and the clock block documentation). In this
case, a precise clock derived from the XE1202A can be used to run the microcontroller in stead of the internal RC
oscillator. The advantage is that the crystal oscillator is much more precise than the internal RC but the overall
power consumption of the system will be somewhat larger.
To enable the external clock output of the XE1202A, set the bit RTParam_Clkout=1 and use the bits
ADParam_Clkfreq[1:0] to select the frequency between 9.75MHz and 1.22MHz (see XE1202A datasheet for
details).
To select the external clock in the microcontroller, set the bit EnExtClk = 1 in the register RegSysClk. Be aware
that the external clock is divided by 2 at the input (see the clock block documentation for more details).
© Semtech 2006
Figure 14-9 : Configuration of the connections between the microcontroller and XE1202A
XE8000
RegRfifRxSPat
RegRfifCmd1
RegRfifCmd2
RegRfifCmd3
RegRfifRxSta
RegRfifTxSta
RegRfifRx
parallel port
RegRfifTx
RFIF0
RFIF1
RFIF2
RFIF3
XIN
MOSI
MISO
SCK
SS
14-21
[match]
[clock]
data
data
CLKOUT
PATTERN
MODE(2)
DATAOUT
CLKD
DATAIN
MODE(0)
MODE(1)
EN
SCK
SI
SO
XE8806A/XE8807A
XE1202A
ADParam1
ADParam2
RTParam1
RTParam1
FSParam1
FSParam2
FSParam3
DataOut
Pattern1
Pattern2
Pattern3
Pattern4
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