From 010c1e3e4007f74253b8819166a2ef77896e3998 Mon Sep 17 00:00:00 2001
From: Brian Peek <2321675+BrianPeek@users.noreply.github.com>
Date: Tue, 27 Sep 2022 23:02:38 -0700
Subject: [PATCH] start of different EPROM sizes

---
 .vscode/extensions.json   | 10 --------
 src/SendEPROM             |  1 +
 src/{ => teensy}/main.cpp | 48 +++++++++++++++++++++++++++------------
 3 files changed, 34 insertions(+), 25 deletions(-)
 delete mode 100644 .vscode/extensions.json
 create mode 160000 src/SendEPROM
 rename src/{ => teensy}/main.cpp (73%)

diff --git a/.vscode/extensions.json b/.vscode/extensions.json
deleted file mode 100644
index 080e70d..0000000
--- a/.vscode/extensions.json
+++ /dev/null
@@ -1,10 +0,0 @@
-{
-    // See http://go.microsoft.com/fwlink/?LinkId=827846
-    // for the documentation about the extensions.json format
-    "recommendations": [
-        "platformio.platformio-ide"
-    ],
-    "unwantedRecommendations": [
-        "ms-vscode.cpptools-extension-pack"
-    ]
-}
diff --git a/src/SendEPROM b/src/SendEPROM
new file mode 160000
index 0000000..852bcbb
--- /dev/null
+++ b/src/SendEPROM
@@ -0,0 +1 @@
+Subproject commit 852bcbb35134d515fa85c28a36daf8a93beeb717
diff --git a/src/main.cpp b/src/teensy/main.cpp
similarity index 73%
rename from src/main.cpp
rename to src/teensy/main.cpp
index db25f40..5caa4d0 100644
--- a/src/main.cpp
+++ b/src/teensy/main.cpp
@@ -2,24 +2,34 @@
 #include <SPI.h>
 #include <SD.h>
 
-// forced to a 2mbit eprom
 // FLASHMEM
 // DMAMEM
 // PROGMEM
 
+enum eMode : unsigned char
+{
+	m27C256 = 1,
+	m27C020 = 2,
+	mUnknown = 0xFF
+};
+
 #define ROM_BUFFER_LEN (256*1024)
 char buffer[ROM_BUFFER_LEN];
 const char *filename = "rom.bin";
+eMode mode = m27C020;
+Stream* stream;
 
 int32_t inPins[] = { 19,18,14,15,40,41,17,16,22,23,20,21,38,39,26,27,24,25,-1 };
 int32_t outPins[] = { 10,12,11,13,8,7,36,37,-1 };
 
-void readFile(int port)
+void readData(Stream* s)
 {
 	const int length = 1024;
 	char buff[length];
 
-	memset(buffer, 0, ROM_BUFFER_LEN);
+	mode = (eMode)s->read();
+
+	memset(buffer, 0xFF, ROM_BUFFER_LEN);
 
 	size_t read = 0;
 	size_t total = 0;
@@ -29,15 +39,7 @@ void readFile(int port)
 	{
 		memset(buff, 0, length);
 
-		switch(port)
-		{
-			case 0:
-				read = Serial.readBytes(buff, length);
-				break;
-			case 1:
-				read = Serial1.readBytes(buff, length);
-				break;		
-		}
+		read = s->readBytes(buff, length);
 
 		total += read;
 		if(read > 0)
@@ -90,7 +92,23 @@ void loop()
 	uint32_t outb = 0;
 
 	// read address pins
-	uint32_t addr = ((io6 >> 16) & 0xFFFF) | ((io6 & 0x3000) << 4);
+	uint32_t addr = 0;
+
+	switch(mode)
+	{
+		// 32Kbit, 8KB, 0x0000-0x7FFF
+		case m27C256:
+			addr = ((io6 >> 16) & 0x7FFF);
+			break;
+
+		// 2Mbit, 256KB, 0x00000-0x3FFFF
+		case m27C020:
+			addr = ((io6 >> 16) & 0xFFFF) | ((io6 & 0x3000) << 4);
+			break;
+
+		default:
+			break;
+	}
 
 	// get byte at addr
 	char b = buffer[addr];
@@ -101,8 +119,8 @@ void loop()
 
 	// read file from either serial port, if available
 	if(Serial.available())
-		readFile(0);
+		readData(&Serial);
 
 	if(Serial1.available())
-		readFile(1);
+		readData(&Serial1);
 }