EM6520 EM Microelectronic, EM6520 Datasheet - Page 29

• Manufacturer Part Number: EM6520
• Description: MFP version of EM6620 Ultra Low Power Microcontroller 4x8 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 Figure 18). In MSC mode the start
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 Figure 20 for details. Afterwards one can change to PA3 controlled
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 20. 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 PA[3] value. See also Figure
18 and Figure 21.
• 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 Figure 18 and Figure 21.
Copyright  2002, 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 = 1 , S t o p o n P A [ 3 ] R i s i n g E d g e
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
status
S t a r t
S t a r t
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
S t o p
S t o p
with
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
29
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
R u n E n / S t o p
P A 3 / u P
P A [ 3 ]
P A 3 I n t e r n a l
C o u n t
C P U W r i t e
P A 3 E d g e
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 21. 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
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
EM6520
Period
Measurem ent
S t o p
S t o p
Pulse-width
restart
stop
Counting
03/02 REV. D/449
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