9 Mode register, MODE

This register controls the TMC operating mode. The operating mode can only be changed when the TMC is in Disabled state, that is, when CTL.TraceCaptEn = 0. Attempting to write to this register in any other state results in UNPREDICTABLE behavior. The operating mode is ignored when in Disabled state.

The MODE register characteristics are:

Attributes
Offset

0x0028

Type

Read-write

Reset

0x0000000-

Width

32

The following figure shows the bit assignments.

Figure 9-371 MODE register bit assignments
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The following table shows the bit assignments.

Table 9-384 MODE register bit assignments

Bits Reset value Name Function
[31:5] 0x0 RAZ/WI

Read-As-Zero, Writes Ignored.

[4] 0b0 StallOnStop

Stall On Stop. If this bit is set and the formatter stops as a result of a stop event, the output atready_s is de-asserted to stall the ATB interface and avoid loss of trace. If this bit is clear and the formatter stops as a result of a stop event, signal atready_s remains asserted but the TMC discards further incoming trace.

[3:2] 0b00 RAZ/WI

Read-As-Zero, Writes Ignored.

[1:0] UNKNOWN MODE

Selects the operating mode. If a reserved MODE value is programmed and trace capture is enabled, the TMC starts to operate in SWF1 mode. However, reading the MODE.MODE field returns the programmed value.

0x0

CB, Circular Buffer mode.

0x1

SWF1, Software Read FIFO mode 1.

0x2

Reserved.

0x3

SWF2, Software Read FIFO mode 2.

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