Serial Periph eral Inter face (SPI)
MPC8260 PowerQUICC II Family Reference Manual, Rev. 2
38-8 Freescale Semiconductor

Figure 38-6. SPI Transfer Format with SPMODE[CP] = 1

38.4.1.1 SPI Examples with Different SPMODE[LEN] Values

The examples below show how SPMODE[LEN] is used to determine character length. To help map the

process, the conventions shown in Table 38-2 are used in the examples.

Once the data string image is determined, it is always transmitted byte by byte with the lsb of the

most-significant byte sent first. For all examples below, assume the memory contains the following binary

image:

msb ghij_klmn__opqr_stuv lsb

Example 1

with LEN=4 (data size=5), the foll ow in g data is selected:
msb xxxj_klmn__xxxr_stuv lsb
with REV=0, the data st ring image is:
msb j_klmn__r_stuv lsb
the order of the string appearing on the line , a byte at a time is:
first nmlk_j__vuts_r last
with REV=1,the string h as each byte reversed, a nd the data string image is:
msb nmlk_j__vuts_r lsb
the order of the string appearing on the line, one byte at a time is:
first j_klmn__r_stuv last

Example 2

Table38-2. Example Conventions

Convention Description
g–v Binary symbols
x Deleted bit
__ 1
1Both __ and _ are used to aid readability.
Original byte boundary
_ 1Original 4-bit boundary.
SPICLK
SPICLK
SPIMOSI
SPISEL
(From Master)
SPIMISO
(From Slave)
(CI = 0)
(CI = 1)
NOTE: Q = Undefined Signal.
msb lsb
lsbQmsb