Nokia RH-3 Series Troubleshooting - Gps page 11

CCS Technical Documentation
Test Mode 1
Test Mode 1 is a built-in self-test (BIST) for the GPS BB ASIC that checks for internal
faults. To implement Test Mode 1, select the test mode 1 radio button and then click the
Execute button in the "Rx simple actions" tab of the GPS component in Phoenix.
Code Download
The code store inside the GPS BB ASIC is volatile. As a result, each time power is applied
to the ASIC, the code that runs there must be re-downloaded from the CE. If this process
does not complete correctly, the GE will not work. The interface protocol utilized for this
process is the Universal Synch/Asynch Receiver Transmitter (USART), and the pins on the
GPS BB ASIC are labeled U1Tx, U1Rx, U1_DATA_RDY, and U1_CLK. To determine if this
interface is active, check for activity on these lines at power up. Each of these lines
should have a short burst of activity immediately after power is applied. To capture these
signals, you will need to set the storage scope to single sweep or triggered mode (see
Figure 5).
SPI Interface
The SPI interface is a three-line synchronous serial interface used by the GPS BB to com-
municate to the GPS RF. These lines are called SPI_CLK, SPI_DATA, and SPI_EN. Activity
should be seen for a short period on these signals each time a mode switch is made (e.g.,
between idle and off mode in the "Rx simple actions" tab of the GPS component in Phoe-
nix). See Figure 6.
Issue 1 06/2003
Figure 5: GPS Code Download U1 CLK U1 RX
Nokia Corporation
Troubleshooting — GPS
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RH-3
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