High-Throughput Avionics Data Bus Optimization

### High-Throughput Avionics Data Bus

A Tier-1 aerospace supplier required a reliable, zero-heap telemetry processor to monitor flight control bus messages. The system must operate under rigid latency bounds without scheduling jitter.

#### Hardware Architecture
We built the pipeline on an **ARM Cortex-M7** processor running at 400 MHz. By utilizing tightly-coupled instruction memory (ITCM) and separating the RX packet buffers into a lock-free ring queue, we eliminated dynamic allocations.

#### Core Code Implementation
The telemetry listener pushes packets to the ring buffer using memory fences to prevent CPU pipelining re-ordering:

“`c
void enqueue_telemetry_packet(const Packet_t *packet) {
uint32_t next = (ring_buffer.head + 1) & BUFFER_MASK;
if (next != ring_buffer.tail) {
ring_buffer.data[ring_buffer.head] = *packet;
__dmb(); // Data memory barrier fence
ring_buffer.head = next;
}
}
“`

#### Results & Validation
– Hardware loop response time reduced to **0.02ms** average.
– Eliminated dynamic heap allocation, satisfying aerospace safety standards (DO-178C Level A).
– Reduced RAM footprint by **98%** compared to the legacy heap-based queue implementation.