Function Headers and Description
10.3.2 Echo_SendData
void Echo_SendData(void);
Syntax:
Parameters: None
Return:
None
Description: Initiates sending a message consisting of a preamble sequence, header, length, data, and
checksum. Length and data are read from the Tx buffer; the header is statically defined in
the Echo.hconfiguration file; and checksum is calculated (and confirmed on reception) by
the driver. During transmission, the status flag BusyTxis set. Switches back to Rx mode on
completion of the transmission.
Notes:
This service requires the driver to be in transmit mode before entry and should be used in
conjunction with the Echo_SendPreambleID()service to send complete messages (see
Figure 8). Before using this function to switch driver mode (both banks are enabled), the
right bank of registers must be set by Echo_ChangeBank(ECHO_BANK_x).
10.3.3 Echo_SendMessage
void Echo_SendMessage(void);
Syntax:
Parameters: None
Return:
None
Description: Switches to Tx mode and initiates the buffered sending of a complete message telegram
sequence consisting of a number of preamble/ID sequences followed the message in the
same format as Echo_SendData(). The number of preamble/ID sequences to repeat and the
spacing between them are defined by parameters in the Tx buffer. During transmission, the
status flag BusyTx is set.
Notes:
The message being sent is copied into an internal buffer, thus freeing the external buffer to
queue another message for transmission. To queue another message, verify the buffer is
empty (using the buffer full bit) and if so, load in the next message. Call
Echo_SendMessage()again, which will set the buffer full flag until the message is copied
into the internal buffer to be sent. At that point another message can be queued. If no new
message is queued at the end of transmission of a message, the mode is switched back to
Rx (incurring a mode switch delay of 500 μs). Before using this function to switch driver
mode (both banks are enabled), the right bank of registers must be set by
Echo_ChangeBank(ECHO_BANK_x).
Software Drivers for MC33696, Rev. 1
Freescale Semiconductor
21
FREESCALE [ Freescale ]
