Control Registers
1197
SPNU503C – March 2018
Copyright © 2018, Texas Instruments Incorporated
Multi-Buffered Serial Peripheral Interface Module (MibSPI) with Parallel Pin
Option (MibSPIP)
24.9.34 TGx Control Registers (TGxCTRL)
Each TG can be configured via one dedicated control register. The register description shows one control
register (x) that is identical for all TGs. For example, the control register for TG2 is named TG2CTRL and
is located at
base a 98h + 4 × 2
. The actual number of available control registers varies by
device.
Figure 24-64. MibSPI TG Control Registers (TGxCTRL) [offsets = 98h-D4h]
31
30
29
28
27
24
TGENA
ONESHOT
PRST
TGTD
Reserved
R/W-0
R/W-0
R/W-0
R-0
R-0
23
20
19
16
TRIGEVT
TRIGSRC
R/W-0
R/W-0
15
14
8
7
6
0
Rsvd
PSTART
Rsvd
PCURRENT
R-0
R/W-0
R-0
R-0
LEGEND: R/W = Read/Write; R = Read only; -
n
= value after reset
Table 24-42. TG Control Registers (TGxCTRL) Field Descriptions
Bit
Field
Value
Description
31
TGENA
TGx enable.
If the correct event (TRIGEVTx) occurs at the selected source (TRIGSRCx), a group transfer is
initiated if no higher-priority TG is in active-transfer mode or if one or more higher-priority TGs are
in transfer-suspend mode.
Disabling a TG while a transfer is ongoing will finish the ongoing word transfer but not the whole
group transfer.
0
TGx is disabled.
1
TGx is enabled.
30
ONESHOTx
Single transfer for TGx.
0
TGx initiates a transfer every time a trigger event occurs and TGENA is set.
1
A transfer from TGx will be performed only once (one shot) after a valid trigger event at the
selected trigger source. After the transfer is finished the TGENAx control bit will be cleared and
therefore no additional transfer can be triggered before the host enables the TG again. This one
shot mode ensures that after one group transfer the host has enough time to read the received
data and to provide new transmit data.
29
PRSTx
TGx pointer reset mode. Configures the way to resolve trigger events during an ongoing transfer.
This bit is meaningful only for level-triggered TGs. Edge-triggered TGs cannot be restarted before
their completion by another edge. The PRST bit will have no effect on this behavior.
Note: When the PRST bit is set, if the buffer being transferred at the time of a new trigger
event is a LOCK, CSHOLD or NOBRK buffer, then only after finishing those transfers, the
TG will be restarted. This means that even if the TG is retriggered, the TG will only be
restarted after finishing the transfer of the first non-LOCK or non-CSHOLD buffer. In the
case of the NOBRK buffer, after completing the ICOUNT number of transfers, the TG will be
restarted from its PSTART.
This means that TX control fields such as LOCK and CSHOLD, and DMA control fields such as
NOBRK have higher priority over anything else. They have the capability to delay the restart of the
TG even if it is retriggered when PRST is 1.
0
If a trigger event occurs during a transfer from TGx, the event is ignored and is not stored
internally. The TGx transfer has priority over additional trigger events.
1
The TGx pointer (PCURRENTx) will be reset to the start address (PSTARTx) when a valid trigger
event occurs at the selected trigger source while a transfer from the same TG is ongoing. Every
trigger event resets PCURRENTx no matter whether the concerned TG is in transfer mode or not.
The trigger events have priority over the ongoing transfer.
28
TGTDx
TG triggered.
0
TGx has not been triggered or is no longer waiting for service.
1
TGx has been triggered and is either currently being serviced or waiting for servicing.