Datasheet

© 2007 Microchip Technology Inc. Preliminary DS70165E-page 329
dsPIC33F
FIGURE 26-13: QEI MODULE INDEX PULSE TIMING CHARACTERISTICS
TABLE 26-30: QEI INDEX PULSE TIMING REQUIREMENTS
QEA
(input)
Ungated
Index
QEB
(input)
TQ55
Index Internal
Position
Counter Reset
TQ50
TQ51
AC CHARACTERISTICS
Standard Operating Conditions: 3.0V to 3.6V
(unless otherwise stated)
Operating temperature -40°C ≤ TA ≤ +85°C
Param
No.
Symbol Characteristic
(1)
Min Max Units Conditions
TQ50 TqIL Filter Time to Recognize Low,
with Digital Filter
3 * N * T
CY — ns N = 1, 2, 4, 16, 32, 64,
128 and 256 (Note 2)
TQ51 TqiH Filter Time to Recognize High,
with Digital Filter
3 * N * T
CY — ns N = 1, 2, 4, 16, 32, 64,
128 and 256 (Note 2)
TQ55 Tqidxr Index Pulse Recognized to Position
Counter Reset (ungated index)
3 T
CY —ns —
Note 1: These parameters are characterized but not tested in manufacturing.
2: Alignment of index pulses to QEA and QEB is shown for position counter Reset timing only. Shown for
forward direction only (QEA leads QEB). Same timing applies for reverse direction (QEA lags QEB) but
index pulse recognition occurs on falling edge.