From 79a4fe33a6d33a34a986dc18a6e3fbeba388a0bc Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Carlos=20P=C3=A9rez=20Penichet?= <cperezpenichet@gmail.com>
Date: Thu, 25 Oct 2018 11:24:44 +0200
Subject: [PATCH] Unmodulated carrier transmission for cc2538

Modified the cc2538 driver to enable the radio test
mode to emit unmodulated carriers (tones).
A carrier can be enabled using the normal radio driver
API:
NETSTACK_CONF_RADIO.set_value(
RADIO_PARAM_POWER_MODE,
RADIO_POWER_MODE_CARRIER_ON);

Once enabled, the carrier can be disabled like this:
NETSTACK_CONF_RADIO.set_value(
RADIO_PARAM_POWER_MODE,
RADIO_POWER_MODE_CARRIER_OFF);
---
 arch/cpu/cc2538/dev/cc2538-rf.c | 59 +++++++++++++++++++++++++++++++--
 1 file changed, 57 insertions(+), 2 deletions(-)

diff --git a/arch/cpu/cc2538/dev/cc2538-rf.c b/arch/cpu/cc2538/dev/cc2538-rf.c
index bddfcc942..32a8eef81 100644
--- a/arch/cpu/cc2538/dev/cc2538-rf.c
+++ b/arch/cpu/cc2538/dev/cc2538-rf.c
@@ -140,6 +140,8 @@ static const output_config_t output_power[] = {
   {-24, 0x00 },
 };
 
+static radio_result_t get_value(radio_param_t param, radio_value_t *value);
+
 #define OUTPUT_CONFIG_COUNT (sizeof(output_power) / sizeof(output_config_t))
 
 /* Max and Min Output Power in dBm */
@@ -394,6 +396,50 @@ get_sfd_timestamp(void)
   return RTIMER_NOW() - RADIO_TO_RTIMER(timer_val - sfd);
 }
 /*---------------------------------------------------------------------------*/
+/* Enable or disable radio test mode emmiting modulated or unmodulated 
+ * (carrier) signal. See datasheet page XX
+*/
+static uint32_t prev_FRMCTRL0, prev_MDMTEST1;
+static uint8_t was_on;
+
+static void
+set_test_mode(uint8_t enable, uint8_t modulated)
+{
+  radio_value_t mode;
+  get_value(RADIO_PARAM_POWER_MODE, &mode);
+  
+  if (enable) {
+    if (mode == RADIO_POWER_MODE_CARRIER_ON) {
+      return;
+    }
+    was_on = (mode == RADIO_POWER_MODE_ON);
+    off();
+    prev_FRMCTRL0 = REG(RFCORE_XREG_FRMCTRL0);
+    // This constantly transmits random data
+    printf("FRMCTRL0: %08X\n", (unsigned int)prev_FRMCTRL0);
+    REG(RFCORE_XREG_FRMCTRL0) = 0x00000042; 
+    if (!modulated) {
+      prev_MDMTEST1 = REG(RFCORE_XREG_MDMTEST1);
+      printf("MDMTEST1: %08X\n", (unsigned int)prev_MDMTEST1);
+      // ...adding this we send an unmodulated carrier instead
+      REG(RFCORE_XREG_MDMTEST1) = 0x00000018;
+    }
+    CC2538_RF_CSP_ISTXON();
+  } else {
+    if (mode != RADIO_POWER_MODE_CARRIER_ON) {
+      return;
+    }
+    CC2538_RF_CSP_ISRFOFF();
+    REG(RFCORE_XREG_FRMCTRL0) = prev_FRMCTRL0;
+    if (!modulated) {
+      REG(RFCORE_XREG_MDMTEST1) = prev_MDMTEST1;
+    }
+    if (was_on) {
+      on();
+    }
+  }
+}
+/*---------------------------------------------------------------------------*/
 /* Netstack API radio driver functions */
 /*---------------------------------------------------------------------------*/
 static int
@@ -806,8 +852,12 @@ get_value(radio_param_t param, radio_value_t *value)
 
   switch(param) {
   case RADIO_PARAM_POWER_MODE:
-    *value = (REG(RFCORE_XREG_RXENABLE) && RFCORE_XREG_RXENABLE_RXENMASK) == 0
-      ? RADIO_POWER_MODE_OFF : RADIO_POWER_MODE_ON;
+    if ((REG(RFCORE_XREG_RXENABLE) & RFCORE_XREG_RXENABLE_RXENMASK) == 0) {
+      *value = RADIO_POWER_MODE_OFF;
+    } else {
+      *value = (REG(RFCORE_XREG_FRMCTRL0) & RFCORE_XREG_FRMCTRL0_TX_MODE) == 0
+        ? RADIO_POWER_MODE_ON : RADIO_POWER_MODE_CARRIER_ON;
+    }
     return RADIO_RESULT_OK;
   case RADIO_PARAM_CHANNEL:
     *value = (radio_value_t)get_channel();
@@ -895,6 +945,11 @@ set_value(radio_param_t param, radio_value_t value)
     if(value == RADIO_POWER_MODE_OFF) {
       off();
       return RADIO_RESULT_OK;
+    } 
+    if(value == RADIO_POWER_MODE_CARRIER_ON ||
+       value == RADIO_POWER_MODE_CARRIER_OFF) {
+      set_test_mode((value == RADIO_POWER_MODE_CARRIER_ON), 0);
+      return RADIO_RESULT_OK;
     }
     return RADIO_RESULT_INVALID_VALUE;
   case RADIO_PARAM_CHANNEL: