+__xdata ao_radio_rdf_running;
+__xdata ao_radio_rdf_value = 0x55;
+
+void
+ao_radio_rdf(int ms)
+{
+ uint8_t i;
+ uint8_t pkt_len;
+ ao_mutex_get(&ao_radio_mutex);
+ ao_radio_idle();
+ ao_radio_rdf_running = 1;
+ for (i = 0; i < sizeof (rdf_setup); i += 2)
+ RF[rdf_setup[i]] = rdf_setup[i+1];
+
+ /*
+ * Compute the packet length as follows:
+ *
+ * 2000 bps (for a 1kHz tone)
+ * so, for 'ms' milliseconds, we need
+ * 2 * ms bits, or ms / 4 bytes
+ */
+ if (ms > (255 * 4))
+ ms = 255 * 4;
+ pkt_len = ms >> 2;
+ RF[RF_PKTLEN_OFF] = pkt_len;
+
+ ao_dma_set_transfer(ao_radio_dma,
+ &ao_radio_rdf_value,
+ &RFDXADDR,
+ pkt_len,
+ DMA_CFG0_WORDSIZE_8 |
+ DMA_CFG0_TMODE_SINGLE |
+ DMA_CFG0_TRIGGER_RADIO,
+ DMA_CFG1_SRCINC_0 |
+ DMA_CFG1_DESTINC_0 |
+ DMA_CFG1_PRIORITY_HIGH);
+ ao_dma_start(ao_radio_dma);
+ RFST = RFST_STX;
+
+ __critical while (!ao_radio_dma_done)
+ ao_sleep(&ao_radio_dma_done);
+ ao_radio_rdf_running = 0;
+ ao_radio_idle();
+ for (i = 0; i < sizeof (telemetry_setup); i += 2)
+ RF[telemetry_setup[i]] = telemetry_setup[i+1];
+ ao_mutex_put(&ao_radio_mutex);
+}
+
+void
+ao_radio_rdf_abort(void)
+{
+ if (ao_radio_rdf_running) {
+ ao_dma_abort(ao_radio_dma);
+ ao_radio_idle();
+ }
+}
+