
DADDR, and NBYTES, which decrement to zero as the transfer progresses, can give an
indication of the progress of the transfer. All other values are read back from the TCD
local memory.
20.5.5.3 Checking channel preemption status
Preemption is available only when fixed arbitration is selected as the channel arbitration
mode. A preemptive situation is one in which a preempt-enabled channel runs and a
higher priority request becomes active. When the eDMA engine is not operating in fixed
channel arbitration mode, the determination of the actively running relative priority
outstanding requests become undefined. Channel priorities are treated as equal, that is,
constantly rotating, when Round-Robin Arbitration mode is selected.
The TCDn_CSR[ACTIVE] bit for the preempted channel remains asserted throughout
the preemption. The preempted channel is temporarily suspended while the preempting
channel executes one major loop iteration. If two TCDn_CSR[ACTIVE] bits are set
simultaneously in the global TCD map, a higher priority channel is actively preempting a
lower priority channel.
20.5.6 Channel Linking
Channel linking (or chaining) is a mechanism where one channel sets the
TCDn_CSR[START] bit of another channel (or itself), therefore initiating a service
request for that channel. When properly enabled, the EDMA engine automatically
performs this operation at the major or minor loop completion.
The minor loop channel linking occurs at the completion of the minor loop (or one
iteration of the major loop). The TCDn_CITER[E_LINK] field determines whether a
minor loop link is requested. When enabled, the channel link is made after each iteration
of the major loop except for the last. When the major loop is exhausted, only the major
loop channel link fields are used to determine if a channel link should be made. For
example, the initial fields of:
TCDn_CITER[E_LINK] = 1
TCDn_CITER[LINKCH] = 0xC
TCDn_CITER[CITER] value = 0x4
TCDn_CSR[MAJOR_E_LINK] = 1
TCDn_CSR[MAJOR_LINKCH] = 0x7
executes as:
1. Minor loop done
→
set TCD12_CSR[START] bit
Initialization/application information
K32 L2A Reference Manual, Rev. 2, 01/2020
474
NXP Semiconductors
Содержание K32 L2A Series
Страница 2: ...K32 L2A Reference Manual Rev 2 01 2020 2 NXP Semiconductors...
Страница 42: ...K32 L2A Reference Manual Rev 2 01 2020 42 NXP Semiconductors...
Страница 122: ...Flash Memory Clock K32 L2A Reference Manual Rev 2 01 2020 122 NXP Semiconductors...
Страница 146: ...Module operation in low power modes K32 L2A Reference Manual Rev 2 01 2020 146 NXP Semiconductors...
Страница 158: ...Debug and security K32 L2A Reference Manual Rev 2 01 2020 158 NXP Semiconductors...
Страница 174: ...Module Signal Description Tables K32 L2A Reference Manual Rev 2 01 2020 174 NXP Semiconductors...
Страница 246: ...Application information K32 L2A Reference Manual Rev 2 01 2020 246 NXP Semiconductors...
Страница 322: ...Kinetis Bootloader Status Error Codes K32 L2A Reference Manual Rev 2 01 2020 322 NXP Semiconductors...
Страница 344: ...Application initialization information K32 L2A Reference Manual Rev 2 01 2020 344 NXP Semiconductors...
Страница 374: ...CMP Trigger Mode K32 L2A Reference Manual Rev 2 01 2020 374 NXP Semiconductors...
Страница 384: ...Functional description K32 L2A Reference Manual Rev 2 01 2020 384 NXP Semiconductors...
Страница 592: ...Application Information K32 L2A Reference Manual Rev 2 01 2020 592 NXP Semiconductors...
Страница 602: ...Initialization and application information K32 L2A Reference Manual Rev 2 01 2020 602 NXP Semiconductors...
Страница 656: ...Functional Description K32 L2A Reference Manual Rev 2 01 2020 656 NXP Semiconductors...
Страница 664: ...Functional Description K32 L2A Reference Manual Rev 2 01 2020 664 NXP Semiconductors...
Страница 744: ...Functional description K32 L2A Reference Manual Rev 2 01 2020 744 NXP Semiconductors...
Страница 762: ...Functional description K32 L2A Reference Manual Rev 2 01 2020 762 NXP Semiconductors...
Страница 806: ...Functional description K32 L2A Reference Manual Rev 2 01 2020 806 NXP Semiconductors...
Страница 868: ...Integer square root K32 L2A Reference Manual Rev 2 01 2020 868 NXP Semiconductors...
Страница 976: ...Functional description K32 L2A Reference Manual Rev 2 01 2020 976 NXP Semiconductors...
Страница 1012: ...Functional description K32 L2A Reference Manual Rev 2 01 2020 1012 NXP Semiconductors...
Страница 1094: ...Functional description K32 L2A Reference Manual Rev 2 01 2020 1094 NXP Semiconductors...
Страница 1132: ...Functional description K32 L2A Reference Manual Rev 2 01 2020 1132 NXP Semiconductors...
Страница 1182: ...Functional description K32 L2A Reference Manual Rev 2 01 2020 1182 NXP Semiconductors...
Страница 1290: ...Functional description K32 L2A Reference Manual Rev 2 01 2020 1290 NXP Semiconductors...
Страница 1344: ...USB Voltage Regulator Module Signal Descriptions K32 L2A Reference Manual Rev 2 01 2020 1344 NXP Semiconductors...
Страница 1356: ...Initialization Application Information K32 L2A Reference Manual Rev 2 01 2020 1356 NXP Semiconductors...