S912XHZ512F1VAG Datasheet, PDF (702/978 Pages) Freescale Semiconductor, Inc – Covers MC9S12XHZ384, MC9S12XHZ256

Chapter 19 Enhanced Capture Timer (ECT16B8CV3)
All bits reset to zero.
Table 19-31. ICSYS Field Descriptions
Field
Description
7:4
SHxy
3
TFMOD
2
PACMX
1
BUFFEN
0
LATQ
Share Input action of Input Capture Channels x and y
0 Normal operation
1 The channel input ‘x’ causes the same action on the channel ‘y’. The port pin ‘x’ and the corresponding edge
detector is used to be active on the channel ‘y’.
Timer Flag Setting Mode — Use of the TFMOD bit in conjunction with the use of the ICOVW register allows a
timer interrupt to be generated after capturing two values in the capture and holding registers instead of
generating an interrupt for every capture.
By setting TFMOD in queue mode, when NOVWx bit is set and the corresponding capture and holding registers
are emptied, an input capture event will first update the related input capture register with the main timer
contents. At the next event, the TCx data is transferred to the TCxH register, the TCx is updated and the CxF
interrupt flag is set. In all other input capture cases the interrupt flag is set by a valid external event on ICx.
0 The timer flags C3F–C0F in TFLG1 are set when a valid input capture transition on the corresponding port pin
occurs.
1 If in queue mode (BUFEN = 1 and LATQ = 0), the timer flags C3F–C0F in TFLG1 are set only when a latch
on the corresponding holding register occurs. If the queue mode is not engaged, the timer flags C3F–C0F are
set the same way as for TFMOD = 0.
8-Bit Pulse Accumulators Maximum Count
0 Normal operation. When the 8-bit pulse accumulator has reached the value 0x00FF, with the next active edge,
it will be incremented to 0x0000.
1 When the 8-bit pulse accumulator has reached the value 0x00FF, it will not be incremented further. The value
0x00FF indicates a count of 255 or more.
IC Buffer Enable
0 Input capture and pulse accumulator holding registers are disabled.
1 Input capture and pulse accumulator holding registers are enabled. The latching mode is defined by LATQ
control bit.
Input Control Latch or Queue Mode Enable — The BUFEN control bit should be set in order to enable the IC
and pulse accumulators holding registers. Otherwise LATQ latching modes are disabled.
Write one into ICLAT bit in MCCTL, when LATQ and BUFEN are set will produce latching of input capture and
pulse accumulators registers into their holding registers.
0 Queue mode of Input Capture is enabled. The main timer value is memorized in the IC register by a valid input
pin transition. With a new occurrence of a capture, the value of the IC register will be transferred to its holding
register and the IC register memorizes the new timer value.
1 Latch mode is enabled. Latching function occurs when modulus down-counter reaches zero or a zero is
written into the count register MCCNT (see Section 19.4.1.1.2, “Buffered IC Channels”). With a latching event
the contents of IC registers and 8-bit pulse accumulators are transferred to their holding registers. 8-bit pulse
accumulators are cleared.
MC9S12XHZ512 Data Sheet, Rev. 1.06
702
Freescale Semiconductor