em6521 EM Microelectronic, em6521 Datasheet - Page 40

• Manufacturer Part Number: em6521
• Description: Mfp Version Of Em6621 Ultra Low Power Microcontroller With 4x20 Lcd Driver
• Manufacturer: EM Microelectronic

• CPU controlled Start and PA[3] controlled Stop.
In this mode setting the bit RunEn =1 while PA3/uP =0 while immediately start the counting action. Afterwards
one needs to prepare for the stop by PA[3]. Therefore the PA[3] start condition must first be fulfilled. This is in
dT mode a rising edge on the PA3internal signal (PA3internal, refer to
condition is a positive pulse on PA3internal signal. The creation of this edge or pulse is done per software by
manipulating the PA3Edge selection. See
stop mode ( PA3/uP =1) where the next positive edge on PA3internal will stop the Counter. In dT mode the
RunEn/stop bit will be cleared with the PA3 stop condition where as in MSC mode MSC mode the RunEn is
not cleared.
Figure 29. CPU controlled Start PA[3] controlled Stop
• Pulse-width measurement of PA[3] Input Signals.
In this mode the bit dT/MSC =1 and PA3/uP =1. Setting
RunEn/stop=1 enables the operation. The first positive
edge on PA3Internal signal will start the counter, the
following negative edge will stop the counter end set bit
RunEn/Stop to 0 . PA3internal signal is a copy of the PA[3]
terminal
PA3Internal has the inverted
F igure 27 and
1 3 6 H
• Port A PA[3] controlled Start and Stop Mode.
In this mode the bit dT/MSC =0 and PA3/uP =1. Setting
RunEn/stop=1 enables the operation. The first positive
edge on PA3Internal signal will start the counter , the
second edge will stop the counter, the third one will restart,
etc, . PA3internal signal is a copy of the PA[3] terminal
status if PA3Edge =1. With PA3Edge =0 PA3Internal has
the inverted PA[3] value. See also
Copyright © 2005, EM Microelectronic-Marin SA
C P U W r i t e
R u n E n / S t o p
P A 3 / u P
P A [ 3 ]
P A 3 E d g e
P A 3 I n t e r n a l
C o u n t
C P U W r i t e
R u n E n / S t o p
P A 3 / u P
P A [ 3 ]
P A 3 E d g e
P A 3 I n t e r n a l
C o u n t
d T / M S C = 0 , S t o p o n P A [ 3 ] R i s i n g E d g e
d T / M S C = 1 , S t o p o n P A [ 3 ] R i s i n g E d g e
status
R
S t a r t
S t a r t
F igure 30.
1 3 7 H
µ P
µ P
if
S t a r t
P A 3
S t a r t
P A 3
PA3Edge =1.
C o u n t i n g
C o u n t i n g
PA[3]
F igure 27 and
1 3 8 H
S t o p
S t o p
with
value.
F igure 29 for details. Afterwards one can change to PA3 controlled
1 3 5 H
V a l u e s
V a l u e s
I n i t i a l
I n i t i a l
S e t
S e t
PA3Edge =0
F igure 30.
1 3 9 H
See also
C P U W r i t e
R u n E n / S t o p
P A 3 / u P
P A [ 3 ]
P A 3 E d g e
P A 3 I n t e r n a l
C o u n t
C P U W r i t e
R u n E n / S t o p
P A 3 / u P
P A [ 3 ]
P A 3 E d g e
P A 3 I n t e r n a l
C o u n t
40
d T / M S C = 0 , S t o p o n P A [ 3 ] F a l l i n g E d g e
d T / M S C = 1 , S t o p o n P A [ 3 ] F a l l i n g E d g e
Figure 30. dT/MSC behavior
PA3 internal
Counter
RunEn
PA3 internal
Counter
RunEn
S t a r t
S t a r t
µ P
µ P
dT/MSC, PA3/up=1
dT/MSC=0,
PA3/up=1
F igure 27). In MSC mode the start
1 3 4 H
S t a r t
P A 3
start
S t a r t
P A 3
start
C o u n t i n g
C o u n t i n g
Counting
Counting
www.emmicroelectronic.com
stop
m easurem ent
EM6521
Period
Measurem ent
S t o p
S t o p
Pulse-width
restart
stop
Counting
V a l u e s
V a l u e s
I n i t i a l
I n i t i a l
S e t
S e t