technical_information
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technical_information [2025/02/24 09:59] giometti [Generators] |
technical_information [2025/02/24 10:02] (current) giometti [Parallel port generator] |
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| To do so the class pps-gen has been added. PPS generators can be | To do so the class pps-gen has been added. PPS generators can be | ||
| - | registered in the kernel by defining a struct pps_gen_source_info as | + | registered in the kernel by defining a ''struct pps_gen_source_info'' as |
| - | follows:: | + | follows: |
| static struct pps_gen_source_info pps_gen_dummy_info = { | static struct pps_gen_source_info pps_gen_dummy_info = { | ||
| Line 161: | Line 161: | ||
| }; | }; | ||
| - | Where the use_system_clock states if the generator uses the system | + | Where the ''use_system_clock'' states if the generator uses the system |
| clock to generate its pulses, or they are from a peripheral device | clock to generate its pulses, or they are from a peripheral device | ||
| - | clock. Method get_time() is used to query the time stored into the | + | clock. Method ''get_time()'' is used to query the time stored into the |
| - | generator clock, while the method enable() is used to enable or | + | generator clock, while the method ''enable()'' is used to enable or |
| disable the PPS pulse generation. | disable the PPS pulse generation. | ||
| - | Then calling the function pps_gen_register_source() in your | + | Then calling the function ''pps_gen_register_source()'' in your |
| initialization routine as follows creates a new generator in the | initialization routine as follows creates a new generator in the | ||
| - | system:: | + | system: |
| pps_gen = pps_gen_register_source(&pps_gen_dummy_info); | pps_gen = pps_gen_register_source(&pps_gen_dummy_info); | ||
| Line 175: | Line 175: | ||
| ===== Generators SYSFS support ===== | ===== Generators SYSFS support ===== | ||
| - | If the SYSFS filesystem is enabled in the kernel it provides a new class:: | + | If the SYSFS filesystem is enabled in the kernel it provides a new class: |
| $ ls /sys/class/pps-gen/ | $ ls /sys/class/pps-gen/ | ||
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| Every directory is the ID of a PPS generator defined in the system and | Every directory is the ID of a PPS generator defined in the system and | ||
| - | inside of it you find several files:: | + | inside of it you find several files: |
| $ ls -F /sys/class/pps-gen/pps-gen0/ | $ ls -F /sys/class/pps-gen/pps-gen0/ | ||
| dev enable name power/ subsystem@ system time uevent | dev enable name power/ subsystem@ system time uevent | ||
| - | To enable the PPS signal generation you can use the command below:: | + | To enable the PPS signal generation you can use the command below: |
| $ echo 1 > /sys/class/pps-gen/pps-gen0/enable | $ echo 1 > /sys/class/pps-gen/pps-gen0/enable | ||
| Line 198: | Line 198: | ||
| ports, for example. | ports, for example. | ||
| - | Parallel port cable pinout:: | + | Parallel port cable pinout: |
| pin name master slave | pin name master slave | ||
| Line 231: | Line 231: | ||
| latencies. But if it is too small slave won't be able to capture clear edge | latencies. But if it is too small slave won't be able to capture clear edge | ||
| transition. The default of 30us should be good enough in most situations. | transition. The default of 30us should be good enough in most situations. | ||
| - | The delay can be selected using 'delay' pps_gen_parport module parameter. | + | The delay can be selected using ''delay'' pps_gen_parport module parameter. |
technical_information.1740387594.txt.gz · Last modified: 2025/02/24 09:59 by giometti
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