19.3.11.3 Reading from a FIFO Buffer
When the CPU transfers the contents of a message object from a FIFO buffer by writing its number
to the CANIFnCRQ register, the TXRQST and CLRINTPND bits in the CANIFnCMSK register should
be set such that the NEWDAT and INTPEND bits in the CANIFnMCTL register are cleared after the
read. The values of these bits in the CANIFnMCTL register always reflect the status of the message
object before the bits are cleared. To assure the correct function of a FIFO buffer, the CPU should
read out the message objects starting with the message object with the lowest message number.
When reading from the FIFO buffer, the user should be aware that a new received message is
placed in the message object with the lowest message number for which the NEWDAT bit of the
CANIFnMCTL register is clear. As a result, the order of the received messages in the FIFO is not
guaranteed. Figure 19-3 on page 1367 shows how a set of message objects which are concatenated
to a FIFO Buffer can be handled by the CPU.
June 18, 20141366
Texas Instruments-Production Data
Controller Area Network (CAN) Module
To Next Page
Loading...
Need help?
General
