**TLSR8232 / BLE SDK 1.3.1: can a connected slave send ATT requests (GATT client role)?**

A4EVA

Hello everyone, after a phone connects to my device, I want the device to read the Current Time characteristic (0x2A2B) from the peer's GATT server (is the same mechanism used by the PineTime's fw called InfiniTime), so the clock sets itself on connection. This is a normal GATT client operation performed by a device that is a slave at link-layer level. **What already works** - Advertising, connection, my own attribute table (including a Current Time Service that the phone can write to). - Power management, suspend, wake on GPIO. **What does not work** Any attempt to send an ATT request to the master produces no response and no error response. **Tests performed** 1. `att_req_read_by_type(buf, 0x0001, 0xffff, uuid, 2)`    The symbol is exported by liblt_5316.a but is not declared in any SDK header and is not used in any vendor example. When called on an active connection, the exported variable `att_req_busy` stays 0 and nothing is transmitted. 2. Manual ATT PDU injection:    `blc_l2cap_pushData_2_controller(connHandle, L2CAP_CID_ATTR_PROTOCOL, pdu, len, 0, 0)`    Incoming traffic monitored with `blc_l2cap_register_customize_handler()`.    - ATT_MTU_REQ (0x02, 3 bytes): the peer replies, opcode 0x03 is received and visible in my handler. So transmission and reception both work.    - Read Request (0x0A), Read By Type Request (0x08), Read By Group Type Request (0x10), Find By Type Value Request (0x06): the call returns BLE_SUCCESS, but no ATT response and no error response is ever received.    - The same requests were also tried with the opcode in the `format` argument and the rest in `pData`, with the same result. 3. Control test: with no PDU sent at all, no 0x03 response appears. This confirms the MTU response in test 2 was caused by my injected PDU and not by the stack itself. The phone side is not the problem: the same phone, with the same nRF Connect GATT server configuration (Current Time Service added), answers the identical requests when the peer is a different watch (PineTime / InfiniTime). **What I've understood so far** - The Developer Handbook AN-19112700-E, page 48, states that the connection state contains Slave Role only, no Master Role. - The library exports `att_req_*`, `l2cap_att_client_handler`, `att_client_handler`, `blm_att_discoveryService` and `blm_att_findHandleOfUuid16`, but none of them is declared in the SDK headers. - Documentation for the single connection SDK describes `blc_gatt_pushReadRequest`, `blc_gatt_pushReadByTypeRequest` and similar APIs in the "ble master GATT" section, available in the ble_master application, where the host layer is implemented in the application code. **Questions** 1. Can a device connected as a slave issue ATT requests to the master with this SDK? If yes, which API should be used, and what initialization is required (for example registering `l2cap_att_client_handler`, or setting `att_client_handler`)? 2. If not: are the responses to such requests discarded by the stack before reaching the application, because no client state machine is active? Is there a documented hook to receive them? 3. Are the `att_req_*` symbols in liblt_5316.a shared code from the master-capable SDK, bound to the master link-layer path (`blm_push_fifo`) and therefore unusable from a slave connection? 4. Is there an SDK version for TLSR8232, or another chip in the same family, where a connected slave can act as a GATT client? Any pointer to an example doing this would be very welcome. Thank you.