C515C_9711 Datasheet, PDF (76/268 Pages) Siemens Semiconductor Group – 8-Bit CMOS Microcontroller

On-Chip Peripheral Components
C515C
6.1.1.3.2 Output Mode
The output mode for a port 5 pin is selected by programming the corresponding direction bit to '0'
(QDL='0'). The content of the port latch determines whether a '1' (QPL='0') or a '0' (QPL='1') is
driven. Figure 6-10 shows the port structure in the output mode driving a '1' while figure 6-11
illustrates the port structure in the output mode driving a '0'.
Delay = 1 State
=1
V_CC
1 _"0"
"1"
p1 ^"0"
p2 ^"0"
p3
QPL
"0"
QDL
"0"
&
PMOD
"1"
HWPD
"1"
=1
Input Data
(read pin)
1
& _"0"
n1
1
V_SS
CMOS
&
"1" Port
Pin
p5
QPL : Port Latch, Output Q
QDL : Direction Latch, Output Q
MCS02651
Figure 6-10
Bidirectional Port Structure - Output Mode - "1"
The FET n1 is switched off. FET p1 is activated for one state if a 0-to-1 transition is programmed to
the port pin, i.e. a '1' is programmed to the port latch which contained a '0' . The FETs p2, p3 are
both active and are driving the '1' at the port pin.
Semiconductor Group
6-13
1997-11-01