Texas Instruments TMS320 2833 Series User Manual

Starttransfer
No
More
data
?
DSP ready
(GPIO12=0)
?
Yes
LoadXD[15:0]withdata
Signalthatdata
isready
(GPIO13=0)
DSP ack
(GPIO12=1)
?
No
Yes
AcknowledgeDSP
(GPIO13=1)
Yes
No
Endtransfer
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Boot ROM
Figure 2-27. XINTF Parallel Mode - Host Transfer Flow
Figure 2-28 and Figure 2-29 show the flow used to read a single word of data from the parallel port. The
loader uses the method shown in Figure 2-11 to read the key value and to determine if the incoming data
stream width is 8-bit or 16-bit. A different GetWordData function is used by the parallel loader depending
on the data size of the incoming data stream.
• 16-bit data stream
For an 16-bit data stream, the function XINTF_Parallel_GetWordData16bit is used. This function reads
all 16-bits at a time. The flow of this function is shown in Figure 2-28.
• 8-bit data stream
For an 8-bit data stream, the function XINTF_Parallel_GetWordData8bit is used. The 8-bit routine,
shown in Figure 2-29, discards the upper 8 bits of the first read from the port and treats the lower 8 bits
as the least significant byte (LSB) of the word to be fetched. The routine will then perform a second
read to fetch the most significant byte (MSB). It then combines the MSB and LSB into a single 16-bit
value to be passed back to the calling routine.

Texas Instruments TMS320 2833 Series Specifications

General

Brand	Texas Instruments
Model	TMS320 2833 Series
Category	Controller
Language	English