NXP Semiconductors MPC5644A, Reference Manual, Page: 1699 / 1735

Development Trigger Semaphore (DTS)
MPC5644A Microcontroller Reference Manual, Rev. 6
Freescale Semiconductor 1699
38.6 Example application
The calibration process of a new engine requires real-time access to calibration tables and the ability to
update the tables in real-time
1
. The DTS module enables this capability by enabling software to assert a
signal to an external device pin to notify an external tool that data is available. The tool can then retrieve
the data.
In this type of application the DTS_SEMAPHORE register and DTS Trigger Output (DTO) signal provide
a mechanism to notify the calibration tool that the calibration variable or variables (or sets of
measurements), up to 32, have been updated with new values and are available for the tool to access.
Address: D0x0008 Access: Restricted R/W
1
1
The e200z4 core and eDMA modules can set bits in the DTS_SEMAPHORE register but cannot clear them—writes
by the core and eDMA are bitwise ORed to the contents of the register. Nexus can only read this register but all bits
are cleared after the read operation.
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
R
ST31 ST30 ST29 ST28 ST27 ST26 ST25 ST24 ST23 ST22 ST21 ST20 ST19 ST18 ST17 ST16
W
RESET:
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31
R
ST15 ST14 ST13 ST12
ST1
1
ST10
ST9 ST8 ST7
ST06
ST5
ST04
ST3
ST02
ST1 ST0
W
RESET:
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
Figure 38-6. DTS_SEMAPHORE register
Table 38-5. DTS_SEMAPHORE field descriptions
Name Description
ST[31:0] Semaphore Trigger
When a core or eDMA writes a logical ‘1’ to a bit, the bit is set. A write of ‘0’ by the core or DMA does
not change the state of the bit.
• All register bits are set to ‘1’ by a device reset.
• A JTAG reset does not change the state of this register.
• The register can be accessed, with restrictions, by any core, DMA or any Nexus RWA.
• For the core or DMA, only 32-bit write or read accesses are valid.
• A core or DMA valid read access returns the current value of the register and leaves the register
unchanged.
0: No flag
1: Flag is set
1. MPC5644A devices also include an MMU modification feature, which enables real-time switching of calibration tables.