Status Word
Table 4. Status Word Field Description
Description
Bit
Name
Enabled
0
1
Enabled
0
1
2
Indicates when the Echo module is enabled.
Echo driver is busy.
Disabled
—
Busy
Busy
MsgReady
There is a message ready in an Rx buffer. The pointer No message
'echoNextMessage' indicates the start of the buffer.
The Checksumbit indicates if this buffer had a
checksum error.
Message
ready in
buffer
3
4
Tx
The driver is currently transmitting information via Echo. Not
transmitting
Transmission
in progress
Rx
A message is being received and processed by the
driver. Check this flag before sending a message to
avoid losing a message.
Not currently
receiving
Receive is in
progress
5
6
7
8
9
Checksum
Overrun
The message at echoNextMessagehas a checksum Checksum ok Checksum
error.
error
All Rx buffers are full and another message has arrived —
with nowhere to be stored.
Buffer
overrun
Mode
Indicates whether Echo is in transmit or receive mode. Receive Mode Transmit
Mode
EnableDelay
ModeSwitchDelay
Echo is powering up out of standby; this takes 2 ms.
—
Echo
powering up
Echo is switching between modes; delay is
—
Echo
approximately 500 μs
switching
modes
10
11
RSSI_Enabled
Indicates if the RSSI module is on or off
RSSI disabled RSSI enabled
RSSI_InProgress
Indicates if the MCU ADC is currently in use by the
driver. When an analog RSSI is requested, the ADC
must be free for the driver to use. This flag indicates
when the application can take control of the ADC again,
if necessary.
ADC free
ADC busy
12
13
14
15
Error
Indicates that an error has occurred with a request, e.g. —
RSSI.
Error
LVD
Indicates Echo has detected its supply voltage is < 1.8 V. —
Low Voltage
Detected
Timeout
SwitchMode
A timeout has occurred when waiting on a byte to be
received.
—
Timeout
occurred
Indicates whether Echo is in bank switching mode.
Only one bank Two banks
active active
Software Drivers for MC33696, Rev. 1
Freescale Semiconductor
11
FREESCALE [ Freescale ]
