Is it possible to use the same resource(e.g GPIO) on each core (HL/RT core)?

Question

Hello, regarding the resource of app_manifest.json, I wonder if I can use the same hardware resource on each core (HL/RT core) with different IDs(e.g GPIO 8/ GPIO9)? I mean that if there is an app__manifest.json of HL core and app__manifest.json of RT core as below and RT core / HL core runs at the same time. Can I control each GPIO from HL/RT core?

# app_manifest.json of HL core

  "Capabilities": {
    "Gpio": [ "$TEMPLATE_LED" ]       # << Actual GPIO ID of TEMPLATE_LED is GPIO 8
  },

# app_manifest.json of RT core

  "Capabilities": {
    "Gpio": [ 9 ]                     # << Actual GPIO ID is GPIO 9
  },

Thanks.

Answer 1

Hiya!

GPIO's are allocated per core in blocks of 4. A block cannot be split across cores. This is roughly described in the documentation. We will update the documentation to provide greater clarity on this point.

You might find this VS Code extension, written by UCL, helpful for peripheral allocation in an application manifest.

In your specific example, GPIO8 and GPIO9 belong to the same GPIO block and therefore cannot be shared between cores.

Again GPIO blocks contain 4 GPIO. Blocks 0, 1, and 2 also double as PWM0, PWM1, PWM2. If PWM0, PWM1, PWM2 are allocated to core, the pins belonging to the respective block should be considered allocated. GPIO blocks are allocated as follows and a block cannot be split across cores.

GPIO Block	GPIOs
0	GPIO0, GPIO1, GPIO2, GPIO3
1	GPIO4, GPIO5, GPIO6, GPIO7
2	GPIO8, GPIO9, GPIO10, GPIO11
3	GPIO12, GPIO13, GPIO14, GPIO15
4	GPIO16, GPIO17, GPIO18, GPIO19
5	GPIO20, GPI21, GPIO22, GPIO23

ISU GPIO are allocated in blocks of 5 and a block cannot be split across cores:

ISU	GPIOs
0	GPIO26, GPIO27, GPIO28, GPIO29, GPIO30
1	GPIO31, GPIO32, GPIO33, GPIO34, GPIO35
2	GPIO36, GPIO37, GPIO38, GPIO39, GPIO40
3	GPIO66, GPIO67, GPIO68, GPIO69, GPIO70
4	GPIO71, GPIO72, GPIO73, GPIO74, GPIO75

I2S GPIO are also allocated in blocks of 5 and a block cannot be split across cores:

I2S	GPIOs
0	GPIO56, GPIO57, GPIO58, GPIO59, GPIO60
1	GPIO61, GPIO62, GPIO63, GPIO64, GPIO65

ADC GPIO are allocated as a single block of 8. The 8 pins can only be used by one core:

ADC	GPIOs
0	GPIO41, GPIO42, GPIO43, GPIO44, GPIO45, GPIO46, GPIO47, GPIO48