From e2d7f413470e306d045e02aac0d8d9728b3ef755 Mon Sep 17 00:00:00 2001
From: Justin Stephens <justephens@protonmail.com>
Date: Thu, 2 Dec 2021 15:31:10 -0500
Subject: [PATCH] Revert "Added support for on-the-fly FIFO refilling in FSK."

This reverts commit 44b7930a0167622763381f6dd39ce34308580941.
---
 src/modules/SX127x/SX127x.cpp | 38 ++++++++---------------------------
 src/modules/SX127x/SX127x.h   |  4 ++--
 2 files changed, 10 insertions(+), 32 deletions(-)

diff --git a/src/modules/SX127x/SX127x.cpp b/src/modules/SX127x/SX127x.cpp
index 5f518a1e..b0f1f8ab 100644
--- a/src/modules/SX127x/SX127x.cpp
+++ b/src/modules/SX127x/SX127x.cpp
@@ -472,15 +472,6 @@ int16_t SX127x::startTransmit(uint8_t* data, size_t len, uint8_t addr) {
     state |= _mod->SPIsetRegValue(SX127X_REG_FIFO_TX_BASE_ADDR, SX127X_FIFO_TX_BASE_ADDR_MAX);
     state |= _mod->SPIsetRegValue(SX127X_REG_FIFO_ADDR_PTR, SX127X_FIFO_TX_BASE_ADDR_MAX);
 
-    // write packet to FIFO
-    _mod->SPIwriteRegisterBurst(SX127X_REG_FIFO, data, len);
-
-    // set RF switch (if present)
-    _mod->setRfSwitchState(LOW, HIGH);
-
-    // start transmission
-    state |= setMode(SX127X_TX);
-
   } else if(modem == SX127X_FSK_OOK) {
     // check packet length
     if(len >= SX127X_MAX_PACKET_LENGTH_FSK) {
@@ -503,29 +494,16 @@ int16_t SX127x::startTransmit(uint8_t* data, size_t len, uint8_t addr) {
     if((filter == SX127X_ADDRESS_FILTERING_NODE) || (filter == SX127X_ADDRESS_FILTERING_NODE_BROADCAST)) {
       _mod->SPIwriteRegister(SX127X_REG_FIFO, addr);
     }
-    
-    // Pre-load the FIFO with message before entering TX mode
-    uint8_t* ind = data;
-    _mod->SPIwriteRegisterBurst(SX127X_REG_FIFO, ind, min(len, 64));
-    ind += min(len, 64);
-
-    // set RF switch (if present) and start transmitting
-    _mod->setRfSwitchState(LOW, HIGH);
-    state |= setMode(SX127X_TX);
-
-    // Re-fill the FIFO on-the-fly as bytes are transmitted
-    while (ind < data + len) {
-      uint16_t flags = getIRQFlags();
-      bool fifo_full = flags >> 15;
-
-      // If FIFO not full, write another byte
-      if (!fifo_full) {
-        _mod->SPIwriteRegister(SX127X_REG_FIFO, *ind);
-        ind++;
-      }
-    }
   }
 
+  // write packet to FIFO
+  _mod->SPIwriteRegisterBurst(SX127X_REG_FIFO, data, len);
+
+  // set RF switch (if present)
+  _mod->setRfSwitchState(LOW, HIGH);
+
+  // start transmission
+  state |= setMode(SX127X_TX);
   RADIOLIB_ASSERT(state);
 
   return(ERR_NONE);
diff --git a/src/modules/SX127x/SX127x.h b/src/modules/SX127x/SX127x.h
index b8347c2c..dc33ec08 100644
--- a/src/modules/SX127x/SX127x.h
+++ b/src/modules/SX127x/SX127x.h
@@ -12,7 +12,7 @@
 // SX127x physical layer properties
 #define SX127X_FREQUENCY_STEP_SIZE                    61.03515625
 #define SX127X_MAX_PACKET_LENGTH                      255
-#define SX127X_MAX_PACKET_LENGTH_FSK                  255
+#define SX127X_MAX_PACKET_LENGTH_FSK                  64
 #define SX127X_CRYSTAL_FREQ                           32.0
 #define SX127X_DIV_EXPONENT                           19
 
@@ -601,7 +601,7 @@ class SX127x: public PhysicalLayer {
     int16_t beginFSK(uint8_t chipVersion, float br, float freqDev, float rxBw, uint16_t preambleLength, bool enableOOK);
 
     /*!
-      \brief Binary transmit method. Will transmit arbitrary binary data up to 255 bytes long.
+      \brief Binary transmit method. Will transmit arbitrary binary data up to 255 bytes long using %LoRa or up to 63 bytes using FSK modem.
       For overloads to transmit Arduino String or C-string, see PhysicalLayer::transmit.
 
       \param data Binary data that will be transmitted.