Chapter 26 eTimer
MPC5602P Microcontroller Reference Manual, Rev. 4
Freescale Semiconductor
733
26.7
Functional description
26.7.1
General
Each channel has two basic modes of operation: it can count internal or external events, or it can count an
internal clock source while an external input signal is asserted, thus timing the width of the external input
signal.
•
The counter can count the rising, falling, or both edges of the selected input pin.
•
The counter can decode and count quadrature encoded input signals.
•
The counter can count up and down using dual inputs in a “count with direction” format.
•
The counter’s terminal count value (modulo) is programmable.
Table 26-21. DREQ
n
field descriptions
Field
Description
DREQ
n
_EN
DMA Request Enable
Use these bits to enable each of the four module level DMA request outputs. Program the DREQ
fields prior to setting the corresponding enable bit. Clearing this enable bit will remove the request
but wíll not clear the flag that is causing the request.
1 = DMA request enabled.
0 = DMA request disabled.
DREQ
n
DMA Request Select
Use these fields to select which DMA request source will be muxed onto one of the two module level
DMA request outputs. Make sure each of the DREQ registers is programmed with a different value
else a single DMA source will cause multiple DMA requests. Enable a DMA request in the channel
specific INTDMA register after the DREQ registers are programmed.
00000Channel 0 CAPT1 DMA read request
00001Channel 0 CAPT2 DMA read request
00010 Channel 0 CMPLD1 DMA write request
00011 Channel 0 CMPLD2 DMA write request
00100 Channel 1 CAPT1 DMA read request
00101 Channel 1 CAPT2 DMA read request
00110 Channel 1 CMPLD1 DMA write request
00111 Channel 1 CMPLD2 DMA write request
01000 Channel 2 CAPT1 DMA read request
01001 Channel 2 CAPT2 DMA read request
01010 Channel 2 CMPLD1 DMA write request
01011 Channel 2 CMPLD2 DMA write request
01100 Channel 3 CAPT1 DMA read request
01101 Channel 3 CAPT2 DMA read request
01110 Channel 3 CMPLD1 DMA write request
01111 Channel 3 CMPLD2 DMA write request
10000 Channel 4 CAPT1 DMA read request
10001 Channel 4 CAPT2 DMA read request
10010 Channel 4 CMPLD1 DMA write request
10011 Channel 4 CMPLD2 DMA write request
10100 Channel 5 CAPT1 DMA read request
10101 Channel 5 CAPT2 DMA read request
10110 Channel 5 CMPLD1 DMA write request
10111 Channel 5 CMPLD2 DMA write request