TC1796
Peripheral Units (Vol. 2 of 2)
General Purpose Timer Array (GPTA)
User’s Manual
24-72
V2.0, 2007-07
GPTA, V2.0
•
activates the service request line SQTk, if LTCCTRk.REN is set to 1,
•
changes the LTCkOUT output line state (set, reset, toggle, unchanged), depending
on bit field LTCCTRk.OCM and the M1I/ M0I input line state,
•
generates and/or passes an action request via the M1O/M0O output lines to the LTC
with higher order number (LTCk+1),
•
sets the event output EO to high level for one
f
GPTA
clock cycle.
Compare Mode
The Compare Mode can be enabled on a low, high, or both levels of the select input line
SI (LTCCTRk.SOL = 1, LTCCTRk.SOH = 1). The current state of SI is indicated by bit
field LTCCTRk.SLL and can be read. When the value of the local input data bus (YI)
matches the LTCXRk contents,
•
The LTCk service request flag is set,
•
The service request line SQTk is activated if LTCCTRk.REN is set to 1,
•
The LTCkOUT output line state is changed (set, reset, toggle, unchanged),
depending on bit field LTCCTRk.OCM,
•
An action request is generated and/or passed via the M1O/M0O output lines to the
LTC with higher order number (LTCk+1),
•
The event output EO is set to high level for one
f
GPTA
clock cycle.
Note: To enable the compare function in all cases (on every timer or compare register
update caused by a software write access, a reset event or a compare match), bits
LTCCTRk.SOL and LTCCTRk.SOH must be set to 1.
An inactive cell (LTCCTRk.SOL = LTCCTRk.SOH = 0, or SI does not match the
programmed value) will transfer the state of the event input line EI to the event output
line EO.
One Shot Operation
When bit LTCCTRk.OSM is set to 1, a self-disable is executed after each LTC event. The
disable state is cleared with the next write access to control register LTCCTRk. The
current state of LTCk can be checked by reading the control register flag bit
LTCCTRk.CEN.
Note: The contents of register LTCXRk is write-protected for Capture_After_Compare in
Single Shot Mode. Write protection is activated when the compare value is
reached and is released after an access to register LTCXRk.