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The PortIn interface is used to read an underlying GPIO port as one value. This is much faster than BusIn as you can read a port in one go, but much less flexible as you are constrained by the port and bit layout of the underlying GPIO ports.
A mask can be supplied so only certain bits of a port are used, allowing other bits to be used for other interfaces.
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// Switch on an LED if any of mbed pins 21-26 is high
#include "mbed.h"
PortIn p(Port2, 0x0000003F); // p21-p26
DigitalOut ind(LED4);
int main() {
while(1) {
int pins = p.read();
if(pins) {
ind = 1;
} else {
ind = 0;
}
}
}
| PortIn | A multiple pin digital input |
| Functions | |
| PortIn | Create an PortIn, connected to the specified port |
| read | Read the value currently output on the port |
| mode | Set the input pin mode |
| operator int() | A shorthand for read |
A multiple pin digital input
class PortIn
Create an PortIn, connected to the specified port
PortIn( PortName port, int mask = 0xFFFFFFFF )
Read the value currently output on the port
int read()
Set the input pin mode
void mode( PinMode mode )
A shorthand for read
operator int()
Arasch Lagies wrote: With the pin functions table I get for the pin sequence p11 to p18 the hex number 0x7878000, so the call here would be PortIn p(Port0, 0x7878000). Is this right? Somehow this does not seem to work.
Have you tried: p(Port0,0x0007F800) The thing is that because you already call Port0, you have to mask inside that port. Not sure, but could be this way.
- tunkki wrote: Arasch Lagies wrote: With the pin functions table I get for the pin sequence p11 to p18 the hex number 0x7878000, so the call here would be PortIn p(Port0, 0x7878000). Is this right? Somehow this does not seem to work.
Have you tried: p(Port0,0x0007F800) The thing is that because you already call Port0, you have to mask inside that port. Not sure, but could be this way.
Actually you should have (Port0, 0x07878000); p11-p18(p0.16-18, p0.23-26) port 0 == 0000 0111 1000 0111 1000 0000 0000 0000
- tunkki wrote: Actually you should have (Port0, 0x07878000); p11-p18(p0.16-18, p0.23-26) port 0 == 0000 0111 1000 0111 1000 0000 0000 0000
Thanks tunkki, (Port0, 0x07878000); p11-p18(p0.15-18, p0.23-26) for port 0 == 0000 0111 1000 0111 1000 0000 0000 0000 works.
Now I only have to take care that the pin sequence using the mask is different to the mbed pins.
I need also a second 8bit connection. One possibility was to use
p9 -> P0.0
p10 -> P0.1
p30 -> P0.4
p29 -> P0.5
P8 -> P0.6
p7 -> P0.7
p6 -> P0.8
p5 -> P0.9
This is port0 == 0000 0000 0000 0000 0000 0011 1111 0011
which is (Port0, 0x000003F3)
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In the above example, how do you know port2 is a group of P21-P26 ?