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Chapter 6 XGATE (S12XGATEV2)
MC9S12XDP512 Data Sheet, Rev. 2.17
Freescale Semiconductor
195
6.3.1.5
XGATE Software Trigger Register (XGSWT)
The eight software triggers of the XGATE module can be set and cleared through the XGATE software
trigger register (
Figure 6-7
). The upper byte of this register, the software trigger mask, controls the write
access to the lower byte, the software trigger bits. These bits can be set or cleared if a "1" is written to the
associated mask in the same bus cycle.
Read: Anytime
Write: Anytime
NOTE
TheXGATEchannelIDsthatareassociatedwiththeeightsoftwaretriggers
aredeterminedonchipintegrationlevel.(seeSection“Interrupts”ofthe
Soc
Guide
)
XGATE software triggers work like any peripheral interrupt. They can be
used as XGATE requests as well as S12X_CPU interrupts. The target of the
software trigger must be selected in the S12X_INT module.
15
0
14
0
13
0
12
0
11
0
10
0
9
0
8
0
7
6
5
4
3
2
1
0
R
W
XGSWT[7:0]
XGSWTM[7:0]
0
Reset
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Figure 6-7. XGATE Software Trigger Register (XGSWT)
Table 6-5. XGSWT Field Descriptions
Field
Description
15–8
XGSWTM[7:0]
Software Trigger Mask
— These bits control the write access to the XGSWT bits. Each XGSWT bit can only
be written if a "1" is written to the corresponding XGSWTM bit in the same access.
Read:
These bits will always read "0".
Write:
0 Disable write access to the XGSWT in the same bus cycle
1 Enable write access to the corresponding XGSWT bit in the same bus cycle
7–0
XGSWT[7:0]
Software Trigger Bits
— These bits act as interrupt flags that are able to trigger XGATE software channels.
They can only be set and cleared by software.
Read:
0 No software trigger pending
1 Software trigger pending if the XGIE bit is set
Write:
0 Clear Software Trigger
1 Set Software Trigger