Preliminary User's Manual l TQMLS1028A UM 0001 l © 2019, TQ-Systems GmbH
Page 8
4.2.2
Self-Reset
The LS1028A CPU can trigger or request a hardware reset via software.
The output HRESET_REQ# is driven internally by the CPU and can be set by software in register RSTCR (bit 30).
RESET_REQ# is returned to RESIN# within the TQMLS1028A (default). No additional feedback is necessary on the carrier board.
When RESET_REQ# is triggered a self-reset is executed.
Depending on how the feedback circuit is designed on the carrier board, the feedback circuit can "override" the internal
feedback and thus, if RESET_REQ# is active, it can either
•
Trigger a reset
•
Not trigger a reset
•
Trigger further actions on the carrier board in addition to the reset
RESET_REQ# is routed to the connector for this purpose (see Illustration 6: Feedback ).
"Devices" that can trigger a RESET_REQ# see (3), chapter 4.8.3.
Illustration 6:
Feedback HRESET_REQ#
4.2.3
JTAG-Reset TRST#
Coupling to PORESET#, optional pull-down to TRST#.
Illustration 7:
Wiring TRST#
