SLLSFS0 April 2024 THVD4421
PRODUCTION DATA
THVD4421 provides complete diagnostic loopback mode for RS-232. This mode internally shorts bus outputs to bus inputs. So, if data is toggled from logic input, data reaches bus and is reflected back on logic buffer output. This enables MCU to detect bus side short (due to connector and cable) by comparing logic input and logic output.
In RS-232 loopback mode, L3 reflects on L2/R2/R3; L4 reflects on L1/R4/R1; enabling to detect short to ground on all bus pins from R1 through R4. RS-232 loopback mode is optimized for -40°C to 85°C ambient temperature. RS-232 diagnostic loopback can be performed on a node even with another node connected via cable, but listening node is not allowed to transmit anything on the RS232 lines while loopback is ongoing.