altos: cc1200: use FIFO threshold pin output for APRS buffering

Instead of polling the device for fifo space, just use the available
pin configuration to figure out if there is enough space for a single
APRS buffer. Then set the APRS buffer size to match the fifo threshold
setting in the chip so that we know we can write the whole APRS buffer
once the pin says there's space.

Signed-off-by: Keith Packard <keithp@keithp.com>

diff --git a/src/drivers/ao_cc1200.c b/src/drivers/ao_cc1200.c
index 6bccb18863f9439ac0f4ed46f76dc7bd90adabcd..cd85f208aa3dd8f6c6a03d7a57cc65ac57d608c9 100644 (file)
--- a/src/drivers/ao_cc1200.c
+++ b/src/drivers/ao_cc1200.c
@@ -185,9 +185,9 @@ ao_radio_fifo_write_fixed(uint8_t data, uint8_t len)
 }
 
 static uint8_t
-ao_radio_tx_fifo_space(void)
+ao_radio_int_pin(void)
 {
-       return CC1200_FIFO_SIZE - ao_radio_reg_read(CC1200_NUM_TXBYTES);
+       return ao_gpio_get(AO_CC1200_INT_PORT, AO_CC1200_INT_PIN, AO_CC1200_INT);
 }
 
 static uint8_t
@@ -482,6 +482,7 @@ static const uint16_t rdf_setup[] = {
  */
 #define APRS_SYMBOL_RATE_E     6
 #define APRS_SYMBOL_RATE_M     1013008
+#define APRS_BUFFER_SIZE       64
 
 static const uint16_t aprs_setup[] = {
        CC1200_DEVIATION_M,     APRS_DEV_M,
@@ -516,6 +517,9 @@ static const uint16_t aprs_setup[] = {
                 (CC1200_MDMCFG2_SYMBOL_MAP_CFG_MODE_0 << CC1200_MDMCFG2_SYMBOL_MAP_CFG) |
                 (CC1200_MDMCFG2_UPSAMPLER_P_8 << CC1200_MDMCFG2_UPSAMPLER_P) |
                 (0 << CC1200_MDMCFG2_CFM_DATA_EN)),
+       CC1200_FIFO_CFG,
+               ((0 << CC1200_FIFO_CFG_CRC_AUTOFLUSH) |
+                (APRS_BUFFER_SIZE << CC1200_FIFO_CFG_FIFO_THR)),
 };
 
 /*
@@ -861,105 +865,58 @@ ao_radio_send(const void *d, uint8_t size)
        ao_radio_run();
 }
 
-
-#define AO_RADIO_LOTS  64
-
 void
 ao_radio_send_aprs(ao_radio_fill_func fill)
 {
-       uint8_t buf[AO_RADIO_LOTS], *b;
+       uint8_t buf[APRS_BUFFER_SIZE];
        int     cnt;
        int     total = 0;
        uint8_t done = 0;
        uint8_t started = 0;
-       uint8_t fifo_space;
 
        ao_radio_abort = 0;
        ao_radio_get(0xff);
-       fifo_space = CC1200_FIFO_SIZE;
-       while (!done) {
+       ao_radio_wake = 0;
+       while (!done && !ao_radio_abort) {
                cnt = (*fill)(buf, sizeof(buf));
                if (cnt < 0) {
                        done = 1;
                        cnt = -cnt;
                }
-#if CC1200_APRS_TRACE
-               printf("APRS fill %d bytes done %d\n", cnt, done);
-#endif
                total += cnt;
 
                /* At the last buffer, set the total length */
                if (done)
                        ao_radio_set_len(total & 0xff);
 
-               b = buf;
-               while (cnt) {
-                       uint8_t this_len = cnt;
-
-                       /* Wait for some space in the fifo */
-                       while (!ao_radio_abort && (fifo_space = ao_radio_tx_fifo_space()) == 0) {
-#if CC1200_APRS_TRACE
-                               printf("APRS space %d cnt %d\n", fifo_space, cnt); flush();
-#endif
-                               ao_radio_wake = 0;
-                               ao_radio_wait_isr(AO_MS_TO_TICKS(1000));
-                       }
-                       if (ao_radio_abort)
-                               break;
-                       if (this_len > fifo_space)
-                               this_len = fifo_space;
-
-                       cnt -= this_len;
-
-                       if (done) {
-                               if (cnt)
-                                       ao_radio_set_mode(AO_RADIO_MODE_APRS_LAST_BUF);
-                               else
-                                       ao_radio_set_mode(AO_RADIO_MODE_APRS_FINISH);
-                       } else
-                               ao_radio_set_mode(AO_RADIO_MODE_APRS_BUF);
-
+               /* Wait for some space in the fifo */
+               while (started && ao_radio_int_pin() != 0 && !ao_radio_abort) {
+                       ao_radio_wake = 0;
                        ao_exti_enable(AO_CC1200_INT_PORT, AO_CC1200_INT_PIN);
-
-                       ao_radio_fifo_write(b, this_len);
-                       b += this_len;
-#if CC1200_APRS_TRACE
-                       printf("APRS write fifo %d space now %d\n", this_len, ao_radio_tx_fifo_space());
-#endif
-                       if (!started) {
-#if CC1200_APRS_TRACE
-                               printf("APRS start\n");
-#endif
-                               ao_radio_strobe(CC1200_STX);
-#if CC1200_APRS_TRACE
-                               { int t;
-                                       for (t = 0; t < 20; t++) {
-                                               uint8_t status = ao_radio_status();
-                                               uint8_t space = ao_radio_tx_fifo_space();
-                                               printf ("status: %02x fifo %d\n", status, space);
-                                               if ((status >> 4) == 2)
-                                                       break;
-                                               ao_delay(AO_MS_TO_TICKS(0));
-                                       }
-                               }
-#endif
-                               started = 1;
-                       }
+                       ao_radio_wait_isr(AO_MS_TO_TICKS(1000));
                }
-               if (ao_radio_abort) {
-                       ao_radio_idle();
+               if (ao_radio_abort)
                        break;
+
+               if (done)
+                       ao_radio_set_mode(AO_RADIO_MODE_APRS_FINISH);
+               else
+                       ao_radio_set_mode(AO_RADIO_MODE_APRS_BUF);
+
+               ao_radio_fifo_write(buf, cnt);
+               if (!started) {
+                       ao_radio_strobe(CC1200_STX);
+                       started = 1;
                }
        }
        /* Wait for the transmitter to go idle */
-       ao_radio_wake = 0;
-#if CC1200_APRS_TRACE
-       printf("APRS wait idle\n"); flush();
-#endif
-       ao_radio_wait_isr(AO_MS_TO_TICKS(1000));
-#if CC1200_APRS_TRACE
-       printf("APRS abort %d\n", ao_radio_abort);
-#endif
+       while (started && ao_radio_int_pin() != 0 && !ao_radio_abort) {
+               ao_radio_wake = 0;
+               ao_exti_enable(AO_CC1200_INT_PORT, AO_CC1200_INT_PIN);
+               ao_radio_wait_isr(AO_MS_TO_TICKS(1000));
+       }
+       if (ao_radio_abort)
+               ao_radio_idle();
        ao_radio_put();
 }