From 1418af3f31895a15bf2dfcbcae652b7583181a68 Mon Sep 17 00:00:00 2001
From: halfbakery <thehalfbakery@gmail.com>
Date: Tue, 15 Sep 2020 21:49:03 +0200
Subject: [PATCH] Fix C2 programmer, incorrect initialization could brick EFM8
 MCUs

---
 lib/C2Programmer-1.0.0/src/c2.cpp | 22 +++++++++++++++++++++-
 lib/C2Programmer-1.0.0/src/c2.h   |  9 ++++++++-
 tasmota/xdrv_06_snfbridge.ino     |  4 ++--
 3 files changed, 31 insertions(+), 4 deletions(-)

diff --git a/lib/C2Programmer-1.0.0/src/c2.cpp b/lib/C2Programmer-1.0.0/src/c2.cpp
index 22bfbaedd..fd7e41af0 100644
--- a/lib/C2Programmer-1.0.0/src/c2.cpp
+++ b/lib/C2Programmer-1.0.0/src/c2.cpp
@@ -204,13 +204,33 @@ uint8_t c2_reset() {
   return C2_SUCCESS;
 }
 
-uint8_t c2_programming_init() {
+uint8_t c2_programming_init(uint8_t devid) {
   c2_reset();
   c2_address_write(C2FPCTL);
   C2_DATA_WRITE_AND_CHECK(C2FPCTL_ENABLE0,   1);
   C2_DATA_WRITE_AND_CHECK(C2FPCTL_CORE_HALT, 1);
   C2_DATA_WRITE_AND_CHECK(C2FPCTL_ENABLE1,   1)
   C2_DELAY_MS(21);
+
+  // device specific initialization, see https://www.silabs.com/documents/public/application-notes/AN127.pdf
+  switch (devid) {
+  case C2_DEVID_UNKNOWN:
+    break;
+  case C2_DEVID_EFM8BB1:
+  case C2_DEVID_EFM8BB2:
+  case C2_DEVID_EFM8BB3:	// C2_DEVID_EFM8LB1 is the same
+    c2_address_write(0xFF);
+    C2_DATA_WRITE_AND_CHECK(0x80, 1);
+    C2_DELAY_US(5);
+    c2_address_write(0xEF);
+    C2_DATA_WRITE_AND_CHECK(0x02, 1);
+    c2_address_write(0xA9);
+    C2_DATA_WRITE_AND_CHECK(0x00, 1);
+    break;
+  default:
+    return C2_BROKEN_LINK;
+  }
+
   return C2_SUCCESS;
 }
 
diff --git a/lib/C2Programmer-1.0.0/src/c2.h b/lib/C2Programmer-1.0.0/src/c2.h
index bc744d02f..0b80c95f3 100644
--- a/lib/C2Programmer-1.0.0/src/c2.h
+++ b/lib/C2Programmer-1.0.0/src/c2.h
@@ -103,6 +103,13 @@ inline void C2D_enable(bool oe) {
 #define C2_INBUSY   0x02
 #define C2_OUTREADY 0x01
 
+// Device families (https://www.silabs.com/documents/public/application-notes/AN127.pdf)
+#define	C2_DEVID_UNKNOWN	0x00
+#define	C2_DEVID_EFM8BB1	0x30
+#define	C2_DEVID_EFM8BB2	0x32
+#define	C2_DEVID_EFM8BB3	0x34
+#define	C2_DEVID_EFM8LB1	0x34
+
 // Layer 1: C2 Programmig Interface (PI) Register access
 void c2_address_write(uint8_t address);
 uint8_t c2_address_read();
@@ -125,7 +132,7 @@ inline uint8_t c2_data_read(uint8_t &d, uint8_t bytes=1) {
 
 // Layer 2: Operations
 uint8_t c2_reset();
-uint8_t c2_programming_init();
+uint8_t c2_programming_init(uint8_t devid);
 uint8_t c2_block_write(uint32_t address, uint8_t *data, uint8_t len);
 uint8_t c2_block_read(uint32_t address, uint8_t *data, uint8_t len);
 uint8_t c2_eeprom_read(uint32_t address, uint8_t *data, uint8_t len);
diff --git a/tasmota/xdrv_06_snfbridge.ino b/tasmota/xdrv_06_snfbridge.ino
index af6f928bd..228564a45 100644
--- a/tasmota/xdrv_06_snfbridge.ino
+++ b/tasmota/xdrv_06_snfbridge.ino
@@ -127,7 +127,7 @@ ssize_t rf_decode_and_write(uint8_t *record, size_t size)
     uint16_t address = h->address_high * 0x100 + h->address_low;
 
     do {
-      err = c2_programming_init();
+      err = c2_programming_init(C2_DEVID_EFM8BB1);
       err = c2_block_write(address, h->data, h->len);
     } while (err != C2_SUCCESS && retries--);
   } else if (h->record_type == IHX_RT_END_OF_FILE) {
@@ -179,7 +179,7 @@ uint8_t rf_erase_flash(void)
   uint8_t err;
 
   for (uint32_t i = 0; i < 4; i++) {  // HACK: Try multiple times as the command sometimes fails (unclear why)
-    err = c2_programming_init();
+    err = c2_programming_init(C2_DEVID_EFM8BB1);
     if (err != C2_SUCCESS) {
       return 10;                 // Failed to init RF chip
     }