RE: nrf52832 nkro

zbxiong — Thu, 19 Dec 2024 05:54:09 GMT

Ok, thanks for your reply!

RE: nrf52832 nkro

Hung Bui — Wed, 18 Dec 2024 10:27:25 GMT

Hi,
I'm afraid I couldn't help on this. We have very limited experience with NKRO.
Our suggestion is to take a look at this open source project:
https://zmk.dev/docs/config/bluetooth

It's based on Zephyr and it has NKRO supported.

RE: nrf52832 nkro

zbxiong — Wed, 18 Dec 2024 01:45:22 GMT

Hung Bui

I read the QMK NKRO generation rules.

nkro is to split the code returned by the key by shifting it and then send it.

#define NKRO_REPORT_BITS 30

typedef struct {
    uint8_t report_id;
    uint8_t mods;
    uint8_t bits[NKRO_REPORT_BITS];
}report_nkro_t;

void add_key_bit(report_nkro_t* nkro_report, uint8_t code) {
    if ((code >> 3) < NKRO_REPORT_BITS) {
        nkro_report->bits[code >> 3] |= 1 << (code & 7);
    }
}

void add_key_to_report(uint8_t key) {
    if (keyboard_protocol && keymap_config.nkro) {
        add_key_bit(nkro_report, key);
        return;
    }
}

void host_nkro_send(report_nkro_t *report) {
    if (!driver) return;
    report->report_id = REPORT_ID_NKRO;
    (*driver->send_nkro)(report);
}

But I don't understand how the NRF52832 receiver sends this data.

        0x05, 0x01,                     // Usage Page (Generic Desktop),
        0x09, 0x06,                     // Usage (Keyboard),
        0xA1, 0x01,                     // Collection (Application),
        0x85, REPORT_ID_KEYBOARD,       //   Report ID
        // bitmap of modifiers
        0x75, 0x01,                     //   Report Size (1),
        0x95, 0x08,                     //   Report Count (8),
        0x05, 0x07,                     //   Usage Page (Key Codes),
        0x19, 0xE0,                     //   Usage Minimum (224),
        0x29, 0xE7,                     //   Usage Maximum (231),
        0x15, 0x00,                     //   Logical Minimum (0),
        0x25, 0x01,                     //   Logical Maximum (1),
        0x81, 0x02,                     //   Input (Data, Variable, Absolute), ;Modifier byte
        // LED output report
        0x95, 0x05,                     //   Report Count (5),
        0x75, 0x01,                     //   Report Size (1),
        0x05, 0x08,                     //   Usage Page (LEDs),
        0x19, 0x01,                     //   Usage Minimum (1),
        0x29, 0x05,                     //   Usage Maximum (5),
        0x91, 0x02,                     //   Output (Data, Variable, Absolute),
        0x95, 0x01,                     //   Report Count (1),
        0x75, 0x03,                     //   Report Size (3),
        0x91, 0x03,                     //   Output (Constant),
        // bitmap of keys
        0x95, (NKRO_REPORT_BITS-1)*8,   //   Report Count (),
        0x75, 0x01,                     //   Report Size (1),
        0x15, 0x00,                     //   Logical Minimum (0),
        0x25, 0x01,                     //   Logical Maximum(1),
        0x05, 0x07,                     //   Usage Page (Key Codes),
        0x19, 0x00,                     //   Usage Minimum (0),
        0x29, NKRO_REPORT_BITS * 8 - 1, //   Usage Maximum (),
        0x81, 3,                        //0x02,   //   Input (Data, Variable, Absolute),
        0xc0,                           // End Collection

RE: nrf52832 nkro

Hung Bui — Wed, 11 Dec 2024 10:27:30 GMT

Hi Zbxiong,
Could you let me know what exactly happen when you try to test ?
There is a related ticket you can find here: Encountered a problem sending more than 6 bytes of data using the hid service

The last reply pointed to this https://learn.adafruit.com/custom-hid-devices-in-circuitpython/n-key-rollover-nkro-hid-device

Could you take a look at the page to see the report there and check if you can use that in your project ?
We have quite limited experience with NKRO here.