Driver Overview
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Optional resources:
— Timer channel—A second timer channel may be used to allow DATACLK to be input as a
clock source for the timer.
— I/O pin—For STROBE line in order to allow the application direct control of Echo on/off
cycling.
— I/O pin—Connects RSSIC to the signal strength measurement and allows Echo to begin an
internal conversion of the signal strength to be placed in the RSSI register. While RSSIC is held
high, conversions continue as long as CONFB is high.
— I/O pin—For ENABLEPA to allow the driver to control an additional external amplifier for
transmission.
— I/O pin—For ENABLELNA to allow the driver to control an additional external amplifier for
reception.
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Driver Overview
The driver is supplied in two C code files – Echo.C and Echo.H.
The application communicates with the driver through the services and globally accessible storage shown
in Table 2 and Table 3.
Table 2. Driver Services
Driver
Echo_Initialize
Function
Sets the initial configuration for Echo and performs essential driver
set up. Must be called before using any other driver service.
Echo_Enable
Turns Echo on; goes into receive mode after 2 ms startup delay.
Turns Echo off; no messages can be received or transmitted.
Returns Echo’s current status.
Echo_Disable
Echo_DriverStatus
Echo_ClearError
Clears the error and timeout flags.
Echo_SendPreambleID
Echo_SendData
Sends a preamble/ID sequence.
Sends the body of a message.
Echo_SendMessage
Echo_SendIDRepeat
Echo_StrobeHigh
Echo_StrobeLow
Sends an entire message telegram.
Sends a message in ID repeat format.
Sets the STROBE line to 1.
Sets the STROBE line to 0.
Echo_StrobeTriState
Echo_TxTimer_Interrupt
Echo_RxSPI_Interrupt
Echo_SetFreq
Tristates the STROBE line.
Used by the driver to generate the transmitted waveform.
Used by the driver to receive and process messages.
Sets Echo frequencies using user friendly-access mode.
Sets Echo frequencies directly.
Echo_SetFreqNoFRM
Echo_Set_RxOnOff
Sets up RXONOFF register.
Software Drivers for MC33696, Rev. 1
Freescale Semiconductor
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FREESCALE [ Freescale ]
