
M451
May. 4, 2018
Page
381
of
1006
Rev.2.08
M4
51
S
E
RI
E
S
T
E
CH
NICA
L RE
F
E
R
E
NC
E
M
A
NU
A
L
PDMA controller will not perform any transfer and then clear this operation request. Finishing this
task will also generate an interrupt to CPU if corresponding PDMA interrupt bit is enabled.
Idle State
Transfer State
OPMODE (PDMA_DSCTn_CTL[1:0]) = 0x1
OPMODE (PDMA_DSCTn_CTL[1:0]) = 0x0
Transfer done
Next Request
Figure 6.7-3 Basic Mode Finite State Machine
Scatter-Gather Mode
Scatter-Gather mode is a complex mode and can perform sophisticated transfer through the use
of the description link list table as shown in Figure 6.7-4. Through operation mode user can
perform peripheral wrapper-around, multiple PDMA task or can be used for data transfer between
varied locations in system memory instead of a set of contiguous locations.
In Scatter-Gather mode, the table is just used for jumping to the next table entry. The first task will
not perform any operation transfer. Finishing each task will generate an interrupt to CPU if
corresponding PDMA interrupt bit is enabled and TBINTDIS (PDMA_DSCTn_CTL[7]) bit is “0”
(when finishing tas
k and TBINTDIS bit is “0”, corresponding TDIFn (PDMA_TDSTS[11:0] for
M451xG/M451xE, PDMA_TDSTS [7:0] for M451xD/M451xC) flag will be asserted and if this bit is
“1” TDIFn will not be active).
If channel n has been triggered, and the operation mode is in Scatter-Gather mode (OPMODE
(PDMA_DSCTn_CTL[1:0]) = 0x2), the hardware will load the real PDMA information task from the
address generated by adding PDMA_DSCTn_NEXT (link address) and PDMA_SCATBA (base
address) registers. For example, base address is 0x2000_0000 (only MSB 16bits valid in
PDMA_SCATBA), current link address is 0x0000_0100 (only LSB 16bits without last two bits [1:0]
valid in PDMA_DSCTn_NEXT), then next DSCT entry start address is 0x2000_0100.
Note that after each task of description link list table has been finished, the content of transfer
count and operation mode in table will be cleared to 0 by hardware. To use the same link list table
for transfer, user must reconfigure transfer count and operation mode.
Содержание ARM Cortex NuMicro M451 Series
Страница 301: ...M451 May 4 2018 Page 301 of 1006 Rev 2 08 M451 SERIES TECHNICAL REFERENCE MANUAL...
Страница 324: ...M451 May 4 2018 Page 324 of 1006 Rev 2 08 M451 SERIES TECHNICAL REFERENCE MANUAL Figure 6 4 18 Checksum Calculation Flow...
Страница 355: ...M451 May 4 2018 Page 355 of 1006 Rev 2 08 M451 SERIES TECHNICAL REFERENCE MANUAL 2 0 Reserved Reserved...
Страница 625: ...M451 May 4 2018 Page 625 of 1006 Rev 2 08 M451 SERIES TECHNICAL REFERENCE MANUAL 00 5 bits 01 6 bits 10 7 bits 11 8 bits...
Страница 721: ...M451 May 4 2018 Page 721 of 1006 Rev 2 08 M451 SERIES TECHNICAL REFERENCE MANUAL the SCL line 1 0 Reserved Reserved...
Страница 1001: ...M451 May 4 2018 Page 1001 of 1006 Rev 2 08 M451 SERIES TECHNICAL REFERENCE MANUAL LQFP 64L 10x10x1 4 mm footprint 2 0 mm 9 2...
Страница 1002: ...M451 May 4 2018 Page 1002 of 1006 Rev 2 08 M451 SERIES TECHNICAL REFERENCE MANUAL LQFP 64L 7x7x1 4 mm footprint 2 0 mm 9 3...
Страница 1003: ...M451 May 4 2018 Page 1003 of 1006 Rev 2 08 M451 SERIES TECHNICAL REFERENCE MANUAL LQFP 48L 7x7x1 4mm footprint 2 0mm 9 4...