问题
Does anybody have any clue how to control the bi-color LED of ACR122U via the method Reader.control() on Android? (library acssmc-1.1.3).
I am reading the API and have no idea what the command description means:
Example:
byte[] command = {(byte) 0xFF, (byte) 0x00, (byte) 0x40, (byte) 0b01110111, (byte) 0x04, (byte) 20, (byte) 30, (byte) 3, (byte) 2};
These things I do not understand:
- Byte 3 (P2): I cannot figure out how to set that up.
- Byte 5 (T1): First cycle state duration that is somehow controlled from byte 3?
- Byte 6 (T2): Second cycle state duration that is somehow controlled from byte 3?
- Byte 7 (number of repetitions): Number of total 1st and 2nd cycle state repetitions?
Some explained examples would be awesome.
回答1:
The command to change the LED state is
+------+------+------+------+------+------+------+------+------+ | CLA | INS | P1 | P2 | Lc | DATA | +------+------+------+------+------+------+------+------+------+ | 0xFF | 0x00 | 0x40 | SC | 0x04 | T1 | T2 | #R | 0x00 | +------+------+------+------+------+------+------+------+------+
where SC defines the state of the LEDs (continuously on/off, blinking), T1/T2 define the blinking wave form, and #R defines the number of repetitions of the blinking wave form.
So the main parameter to define how the LEDs should blink and how they should look after blinking finished is SC. This is a field of 8 bits:
- Bit 0: This flag defines the state of the red LED after blinking finished (see also bit 2).
- Bit 1: This flag defines the state of the green LED after blinking finished (see also bit 3).
- Bit 2: Only if this flag is set (1), the state of the red LED will be set to the value of bit 0 after blinking finished. If this flag is cleared (0), the red LED will return to the state that it had before you issued LED control command.
- Bit 3: Only if this flag is set (1), the state of the green LED will be set to the value of bit 0 after blinking finished. If this flag is cleared (0), the green LED will return to the state that it had before you issued LED control command.
- Bit 4: This flag defines the state that the red LED should be set to at the beginning of executing the LED control command.
- Bit 5: This flag defines the state that the green LED should be set to at the beginning of executing the LED control command.
- Bit 6: This flag defines if the red LED should be toggled with the blinking wave form.
- Bit 7: This flag defines if the green LED should be toggled with the blinking wave form.
So lets assume that you set bits 4 and 6 of SC (and clear the rest), i.e. SC = 0x50. Further, you set T1 = 5 (0x05), T2 = 10 (0x0A), and #R = 2 (0x02). Thus, you have the following command:
+------+------+------+------+------+------+------+------+------+ | 0xFF | 0x00 | 0x40 | 0x50 | 0x04 | 0x05 | 0x0A | 0x02 | 0x00 | +------+------+------+------+------+------+------+------+------+
Then the green LED will be off and the red LED will blink two times with the following wave form:
RED ON ----------\ /----------\
| | |
RED OFF \--------------------/ \--------------------
\________/ \__________________/ \________/ \__________________/
T1 = 500ms T2 = 1000ms T1 = 500ms T2 = 1000ms
\_____________________________/ \_____________________________/
Repetition 1 Repetition 2
Now, lets assume that you also want to blink the green LED, but with its initial state set to off (so that blinking switches between red and green instead of red and no light). Therefore, you also set bit 7 of SC, i.e. SC = 0xD0. Thus, you have the following command:
+------+------+------+------+------+------+------+------+------+ | 0xFF | 0x00 | 0x40 | 0xD0 | 0x04 | 0x05 | 0x0A | 0x02 | 0x00 | +------+------+------+------+------+------+------+------+------+
Then the red LED and the green LED will alternately blink two times with the following wave form:
RED ON ----------\ /----------\
| | |
RED OFF \--------------------/ \--------------------
GREEN ON /--------------------\ /--------------------
| | |
GREEN OFF ----------/ \----------/
\________/ \__________________/ \________/ \__________________/
T1 = 500ms T2 = 1000ms T1 = 500ms T2 = 1000ms
\_____________________________/ \_____________________________/
Repetition 1 Repetition 2
Now, lets assume that after blinking finished, you want the red LED to be continuously on and the green LED to be continuously off. You therefore need to set bits 2 and 3 in order to be able to define a final state of the two LEDs. (If you do not set those bits, then the values of bits 0 and 1 will simply be ignored.) You then want to define a final state of red on (bit 0 = 1) and gree off (bit 1 = 0). Consequently, you get SC = 0xDD. Thus, you have the following command:
+------+------+------+------+------+------+------+------+------+ | 0xFF | 0x00 | 0x40 | 0xDD | 0x04 | 0x05 | 0x0A | 0x02 | 0x00 | +------+------+------+------+------+------+------+------+------+
Then the red LED and the green LED will alternately blink two times, the red LED will be turned on after blinking, and the green LED will be turned off. You get the following wave form:
RED ON ----------\ /----------\ /--------------...
| | | |
RED OFF \--------------------/ \--------------------/
GREEN ON /--------------------\ /--------------------\
| | | |
GREEN OFF ----------/ \----------/ \--------------...
\________/ \__________________/ \________/ \__________________/
T1 = 500ms T2 = 1000ms T1 = 500ms T2 = 1000ms
\_____________________________/ \_____________________________/ \_____________...
Repetition 1 Repetition 2 Final state
Finally, you want to reduce the number of repetitions to 1 (#R = 0x01) and you want to invert the high and low phases of the blinking wave form (T1 = 0x0A and T2 = 0x05). Thus, you have the following command:
+------+------+------+------+------+------+------+------+------+ | 0xFF | 0x00 | 0x40 | 0xDD | 0x04 | 0x0A | 0x05 | 0x01 | 0x00 | +------+------+------+------+------+------+------+------+------+
You get the following wave form:
RED ON --------------------\ /--------------...
| |
RED OFF \----------/
GREEN ON /----------\
| |
GREEN OFF --------------------/ \--------------...
\__________________/ \________/
T1 = 1000ms T2 = 500ms
\_____________________________/ \_____________...
Repetition 1 Final state
来源：https://stackoverflow.com/questions/38676069/acr122u-led-controlling